Swapping Out to a SMALLER MALE Duraspark Distributor Cap, Best Kept Secret in the Ford Community

I like the simplicity and tuneability of the Duraspark distributor BUT I don't like the big distributor cap. Easy enough to replace with a points distributor type cap BUT that requires a different plug wire configuration due to the points cap being female and the Duraspark cap being mail. I wanted a smaller male cap for my Duraspark distributor AND I FOUND ONE! MAny have said "if you use that smaller cap your ignition WILL crossfire!" That is a myth and here is why • Smaller Male Duraspark...
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[@argee55]

I've been a Ford guys since my teens. I've worked on a bunch of Fords over the past 50 years. I could have used this info more that once. Goes to show that you're never to old to learn.

[@dazecars]

There is so much info out there, I would love to know all the tips and tricks I don't know.

[@LoganPEade]

Pretty much the same here. Sometimes you just want to kick yourself!

[@nova467spanker]

@@dazecars will this work with the Duraspark 335 series engine distributors - the 351m/400?

[@dazecars]

I believe so@@nova467spanker

[@Drmcclung]

​@@nova467spankerit does, very common among Fox guys where there's practically no room for the big cap and most popular intakes, and Lima 4's using this distributor modded in where the large cap physically isn't an option (that's going back some years to the turbo 4 days)

[@Wazoo117]

My dad did this swap to his mom's 66 galaxie w/390 back in the 80's. He used it to trigger a crysler ignition box, works flawlessly to this day because now i drive it

[@dazecars]

I have heard a lot of success stories after uploading this video

[@thisisyourcaptainspeaking2259]

The gm hei module can be used too, just have to mount it on a heatsink. This is what I'm doing if my duraspark module ever fails. I have to look at how/when the hei module triggers, get the trigger leads wired in the correct orientation, I've forgotten.

[@dazecars]

While the GM module is more reliable than the Ford Duraspark box, the spark begins to taper above 3000 RPM so I am not a fan of it as a way to control spark in any sort of performance application. An MSD box is a much better option IMHO and eliminates the need for an OEM ignition box from any manufacturer.

[@thisisyourcaptainspeaking2259]

@@dazecars I've heard this about the gm module before and suspect it's a rumor or reference to low quality replacement. Also, there are several configurations, so no telling what they saw. The hei module has always worked fine for my purposes (non-turbo) up to as much as 5,000 rpm WOT, I don't recall ever turning more than this.

[@dazecars]

I'm not saying that the HEI module will not work above 3000 RPM it does but it is a fact that all OEM HEI modules begin to taper the spark at 3000. Not sure why GM thought that was a good idea. If you use a Pertronix HEI module it will eliminate that taper and you will see even better performance at the upper RPM range.

[@johnp1966]

I've been using the IH cap for the last 10 years

[@dazecars]

you are one of the few that knew this secret. So far only the second I have found.

[@tommy98271]

Absolute genius! How in the hell is the first time I’ve heard of this? You’re the Man.

[@dazecars]

That’s basically what I said when I found out

[@jamesgeorge4874]

Found out about this around 1988, at the junkyard, that the distributor base diameter is the same for TFI, DuraSpark, and points style Ford / Lincoln/ Mercury distributors..

[@dazecars]

Definitely information that a few have but as a whole not mainstream information. Thanks for commenting.

[@piercehawke8021]

Thinking back on it; I strongly suspected the the distributor bodies being concerned had identical dimensions hence the aller cap/rotor

[@dazecars]

interesting

[@richceglinski7543]

The first Ford duraspark in 73 and74 had the small cap with female wire holes. They went to a spacer and lar ger cap in 1975 to prevent crossfire inside the cap with the higher voltage output and to prevent crossfire externally during high humidity/rainy conditions given the front distributor location. Same for GM hei. That said many more current Oem systems seem had returned to smaller caps before distributors became obsolete.

[@dazecars]

The theory that the bigger cap was to avoide crossfire is a logical theory but the closer you look it really dpesn't hold up. it's all theories and conjecture. Only the Ford engineers in the 70s really know. If the bigger cap was truly better high energy aftermarket systems like PerTronix and MSD would use this bigger cap, but they don’t. Their caps are no bigger than the international cap featured in this video. The prevailing "wisdom" as to why Ford made the switch was to avoid crossfire but if the duraspark suffered from crossfire there was some other factor like cheaper spark plug wires or other inferior materials they were compensating for as aftermarket systems don't have this problem and they run even hotter. Another theory is the bigger rotor allows for a longer spark duration for emissions. That is plausible but given the circumference os bigger the rotor is traveling faster so I not sure I agree with that one either. Regardless of why Ford did it, International ran this cap using all duraspark parts on almost everything V8 for 20 years so it clearly works and had it been problematic they would have done what was cheap and easy and switched to what Ford was already using.

[@hotrodray6802]

Yes but those days they used carbon core wires for suppression and most had 8000 ohms per ft. Modern HIPO helical core wires usually have less than 200 ohms and suppress better. Wire resistance causes spark jumping in caps.

[@P_RO_]

@@hotrodray6802 I ran the stock duraspark small cap female connection setup on a mild 302 with old-style "Mr Gasket" cut to fit 8mm resistance wires and never had a single problem with any ignition parts in 285K miles. I did pull the cap and dry-wipe it a few times as I checked on the rotor. I replaced the plugs at 50K thinking they needed it but I was wrong- they were like new. The next 235K miles were with the second set of plugs. The key is (other than wires) it was all OEM Ford, no aftermarket stuff. I've replaced tons of failed aftermarket stuff on these.

[@KC9UDX]

The MSD distributor for this application is horrible!

[@stevendonnalammar4422]

Ford did make the cap bigger to eliminate cross spark but not just because the Dura-Spark II system used higher voltage. My 76 f250 with a 390 in it had dura-spark II with a small female terminal cap. They switch to the larger cap in 77 I think on trucks I'm not sure when they switched on cars but they did it because they made the rotor tip about three times wider because they were trying to be able to deliver the spark through a wider curve. This necessitated a bigger cap to eliminate cross spark issues. Aftermarket companies such as MSD simply didn't worry about this and went back to a narrow terminal rotor, Ford themselves went back to this in the 1980s with the introduction of computer-controlled systems because they were able to more finely tuned the timing via the computer.

[@TradeWorks_Construction]

I’m a Chevy guy, like many others my preferences were heavily influenced by the purchases of my Grandfather and Parents (Thank god Buicks didn’t stick). Despite never owning a Ford and no plan to ever purchase one, I gotta give a shout out to the guy who made this knowledge available and you for publishing it on a social platform w/ a much larger audience. Builder tips this simple and clean probably exist for a lot of other types of builds but stay buried w/o ever having the chance to reach others who could benefit from knowing. So regardless of the specific application I’m all for helping bring more exposure to videos like these! Keep up the good work 👍

[@dazecars]

Thanks, and I agree there are so many gems of wisdom that are getting lost. When we had forums as the main way help each other the info was accessible but now with social media being two easy tips like this get buried under pic of people standing by their car. It is really quite sad.

[@jtto6364]

Yep yep Thanks:):):)

[@garymatthys3605]

@@dazecars you can also use the DS-II distributor to run a GM HEI 4 pin module. Which allows use of E-core coil instead of the oil filled coil.

[@dazecars]

I use the MSD box

[@Hjfvvdst]

I've been a ford guy for 50 years. I always moved to a dura spark. But I had no idea about the small cap until now. Thanks 👍

[@dazecars]

Glad to help

[@robertlessel5025]

This IH cap & rotor should work great on a 351C 4V with a Tunnel Ram set up.

[@dazecars]

yes it should

[@frankalbergo8120]

I'm a life long Ford guy and never knew this. Thanks.

[@dazecars]

glad I could help

[@markparent3323]

I'm not even a "Ford guy" and I found this extremely interesting. Thank you.

[@ThePaulv12]

Yeah I like 100miles from the ocean and I enjoy watching safe bar crossing vids, so I'm hearin' ya lol

[@dazecars]

Glad you enjoyed it

[@ryanmuir6338]

I liked the Duraspark cap on my 351W with Ford Motorsport ignition that I had on my 69 Mach 1. There was room for all the plug boots instead of them being all stuffed together.

[@dazecars]

That is one advantage and a big reason I think Ford did it.

[@robschaffer2189]

I like the big cap. I even run it on my points distributors. It's easier to make the wires look good - like someone else addressed earlier. I work for Ford and the engineering team said it was to keep the wries apart and to a lesser extent reduce tracing in the cap. I just think it looks cool.

[@dazecars]

I will agree with that it is easier to install and route the wires.

[@albertheidger645]

For a cap it's bigger, but works better. There is problems with intake and multi carb systems. Just make sure it fits with the better cap. A better ignition is better than a inferior ignition. Easy fix for clearance issues. Better fix is to think about that before you pay good money for something that doesn't fit. I always liked the big cap. Have made a few point systems with the big cap. Quality cap, rotor, wires on some of the old dual point distributors make for easier adjustments to dwell with the thinner cap and collar. Old torker high rise no problem. Worked better for me. That car ran better with just that change. It had the old mechanical (spring advance distributor of a 289 hi-po) Always wonder how it would have done with a pick-up and box on the side. I also hooked up the higher volt coil from a dura spark II. Thing had a bit hop off the line with 4.56 gears. One of the many rides I remember with fondness. You just tip in with that mechanical advance it had wonderful throttle response. Plugs always had perfect brownish to little lean. I like the big cap.

[@dazecars]

you may like it but I am not convinced its "better". Its ugly, it flops around and If the bigger cap was truly better high energy aftermarket systems like PerTronix and MSD would use this bigger cap, but they don’t. Their caps are no bigger than the international cap featured in this video. International ran this cap using all duraspark parts on almost everything V8 for years and AMC, Jeep and Chrysler used the duraspark with the points cap so it clearly works and had crossfire or tracing been problematic they would have done what was cheap and easy and switched to the bigger cap Ford was already using.

[@user-me3er7lm1o]

@@dazecars- ive got several MSD distributors and they both came equipped from MSD with the big cap. Moroso and MSD made a dual input distributor for NASCAR so the car could be equipped with redundant ignition systems that consisted of two MSD boxes and two coils for reliability. If one system failed the driver flipped a switch to run the back up system. Both of those distributors used the big cap. If NASCAR preferred the big cap then I’m thinking the big cap makes for a better design. The MOROSO distributor was no joke and was very expensive.

[@dazecars]

Those are old school distributors or race distributors. Back in the late 90s MSD had a big cap almost identical to the Ford distributor cap but most of their modern ones are almost identical to the cap in this video. The video that drops this Saturday I hold a modern MSD distributor next to a Duraspark distributor with the International cap and the shape, size, and design of the cap is almost identical. The Nascar "proof" does not really prove anything because the applications are so completely different. The thing that has the biggest impact on crossfire is RPM. An engine that spends a lot of time above 5000 (nascar is almost double that) like a racing application is going to benefit from a bigger cap no argument at all and if you are racing you are not likely running a duraspark distributor to begin with. For a non race application how much time does that engine spend above 5000... little to none. The upcoming video rebuts all the "that cap will cause crossfire" comments I have gotten. Is crossfire possible with the international cap, yes given the correct circumstances ANY distributor can crossfire. Is it likely to crossfire in a street application with quality plug wires NO.

[@McGuigan21]

Thanks for the info Daze. Potentially will solve an "issue" that I have with my duraspark, and that's movement between the cap and adapter. There's a little more slop in there than I personally like, and 1 piece should tighten that up, plus give it more of a vintage look.

[@dazecars]

Glad to help

[@Drmcclung]

The big problem living with the two piece design in damp dewy places was moisture getting inside, constantly eating Ford ignition modules and making white crusties on the terminals (excessive noise and resistance) among other fun things.. but a huge plus worth it in some applications was less crosstalk between terminals.

[@dazecars]

Slop is another issue with a 2 piece. A 1 piece fits with little to no play.

[@Drmcclung]

@@dazecars that reason alone with any of them from all replacement brands is why I try to avoid distributors wherever I can anymore these days, money permitting of course.. quality stepped up in recent years with better cheaper DIS conversions than we had just 5-6 years ago. Particularly like the cam sensor/oil pump drive unit with crank trigger on the main pulley approach when going port injected, or the simple crank trigger/oil drive when going distributorless & carb. No idea when the 'parts fiasco' will ever improve just beware of brand new whole distributors if eventual (probable) slop is a concern

[@johnjohnsn7633]

That's why use use "aftermarket" caps and rotors which utilize brass terminals and blades. No "crusties".

[@Drmcclung]

@@johnjohnsn7633 Does that keep the hard starting moisture out in swampy climes...

[@johnjohnsn7633]

@@Drmcclung For that, try WD40. 😏

[@JG-kv4oi]

Back in the 90's I ran the small cap on a Duraspark distributor, deleted the blue grommet old Echlin part # TP40 Ford control box and wired the distributor instead with the more durable GM control module that they used to put inside the GM distributors after 1975. All this on an 82 Ford 302 V8, worked very well and was dependable.

[@dazecars]

Ford, International, and GM, really mixing it up 😂

[@jeff7.629]

I thought I was the only one that had a Duraspark distributor wired to a HEI module.

[@danbob1650]

Oh the six banger falcon guys know gm trick ... I haven't yet but in the plan

[@garymatthys3605]

@@jeff7.629 That's how mine is set up too

[@douglorimer5985]

I did the same thing in a head to head comparison, and lost power, however it did work.

[@Mustsed]

Great info Daze! Thanks for sharing. Lot's of secrets still out there yet to be discovered.

[@dazecars]

Any time!

[@robertlark7751]

Fantastic bit of information that will be put to use on one of my builds.

[@dazecars]

Glad it was helpful!

[@joell439]

Pure gold. Thanks for this effective and highly valuable nugget 👏👏

[@dazecars]

Glad it was helpful!

[@ProjectFairmont]

Wow. That is awesome. I have always used Duraspark dizzy’s with Mallory ignition boxes. I am currently putting a freshened 289 in a ‘73 Pinto, with an eye toward OEM in appearence as if Ford made a SBF an option for the Pinto in ‘73. That IH small cap is perfect as that looks like a points dizzy. Thank you for sharing!

[@dazecars]

My pleasure!!

[@robertfitzgerald3432]

Thank you. I have some personal thoughts on the Duraspark distributor that some who are using it on older (70-90) Engines, namely in my case 351 Windsor. I have two points to make: 1: DS Caps w/out the breather have a tendency (My case - ever Spring and Fall) to sweat inside, I always had a spare cap in my 78 E150 as each spring and each fall in muggy rain conditions my engine would not start. I simply grabbed the spare cap and replaced the sweaty Cap causing cross sparking and boom!, away it went, and I was good until the next seasonal change. 2: After owning the Van since new (78), in about (80) I began having starting problems in hot weather after stopping BRIEFLY for Gas.. Store... It would start after about 25 minutes but as you can see it was a big pain in the ass. After two starters and a battery I finally figured-out (elimination process..Coil, E-Box...) I changed-out the Magnetic Pick-up and never had the problem again.

[@dazecars]

good information, thanks for sharing

[@ArnCital]

summit has the cap for about $30 and rotor for $5. Mine: '85 460 truck. I kept the Duraspark as during cranking it automatically retards the timing about 4 degrees or so to prevent kickback on the starter. I use the Duraspark to drive an MSD for hotter, multiple spark. Duraspark modules in a F-250 are notorious for failure so I mounted a 2nd one close to the first so I only have to swap the plugs. There is a turbo version of the Duraspark with both 4 and 8 degree retard with the 8 for boost applications. If you replace a dizzy then make certain the drive gear rests on the block boss by the cam otherwise the roll/c pin will shear--I learned that the hard way with a 'new' chima dizzy. Now if I can find a good rebuilder for my spare dizzy ...

[@dazecars]

I run it the exact same way, MSD and duraspark as a trigger

[@DidntSay]

It’s not just F250’s. My ‘77 F150 w/460 killed them too. It’s the heat!! Electronics hate heat! Ever see the goo melting onto the fender rail? Simple solution… air flow. I used (3) 1” pieces of ¼” SS brake tubing and (3) 1 ¾” machine screws to space the module away from the fender rail so that air flows behind it. No more dead modules in the Oklahoma summer. Note: I still keep a spare NIB behind the seat, JIC.

[@dazecars]

Truer words were never spoken, heat and electronics do not mix, especially electronics of 50 years ago but even todays electronics while they do better with heat it's still not a good combo.

[@stevea6722]

Excellent ! Should help with some clearance problems.

[@dazecars]

Yes it should , glad you like it. Please tell your friends 😁

[@Aint_no_senators_son]

Thanks! This is the kind of stuff I used to learn from hot rod magazines

[@dazecars]

Glad to help

[@galaxieman1964]

I had been wondering this for a long time for a Ford of mine. Thank you. I just ordered them before your vid was even finished!!

[@dazecars]

Glad I could help!

[@troywilliams2630]

The bigger cap was to have more spacing between the connectors on the cap from what I understand ! I'm sure Ford had their reasons . But would like to know more . Someone may have more info . But loved this info . Can't believe I've not heard of it . I bleed Ford blue ! 😊

[@dazecars]

There are three prevailing theories: crossfire inside the cap, crossfire outside the cap, and to increase spark duration for better emissions. While crossfire is a potential issue with any cap especialyas RPM goes up, if that was the reason it was to compensate for some cost saving thing like cheaper spark plug wires. Duraspark was used on tones of AMC, International, and even some Chrysler vehicles and non of them use a bigger cap, only Ford. Most use the female type points cap. So while crossfire is a possible reason I don't buy in as MSD and Pertronics distributors are hotter and use a cap of similar size. The "longer spark" theory seams to totally make sense when you look at the tip of the rotors and see the bigger rotor tip is almost twice as wide, but the terminals inside the bigger cap are smaller and the rotor tip for the bigger cap has to move faster because it has further to travel so I don't buy into that either. Ultimately this is all speculation however many view the crossfire theory as gospel. I would love to talk to a 70s Ford engineer to find out for sure. The one thing I believe firmly is for Ford to be the only manufacturer to do it, it was likely somehow a cost saving measure.

[@karljay7473]

I thought the large cap took care of any interference between the posts. I upgraded from the small cap to the large camp specifically to reduce interference.

[@dazecars]

That is a theory but we really don’t know why ford did it exactly. Maybe to eliminate crossfire inside the cap, maybe outside, or maybe some other reason we don’t know. What I do know is it was likely to cut costs somewhere else like maybe spark plug wire quality. Aftermarket high voltage setups like MSD use a similar caps without issue and international used it for 20 years so it is likely not that big of a concern if using quality parts .

[@karljay7473]

@@dazecars it was about 25 years ago when I rebuilt a 428 cobra jet for my truck. Back then it was a known upgrade, I can't say I've had problems either way, with the old set up for the new set up.

[@dazecars]

interestingly enough I am not finding many who have said it was a problem even with a hot ignition. @@karljay7473

[@LoganPEade]

That's just too cool, yes I wish I'd known about it years ago! *_Thank you!_*

[@dazecars]

you're very welcome!

[@comanche678]

Sometimes a video pops up in the recommended and it’s a true gem, already got this in my Amazon cart. Just looks so much cleaner.

[@dazecars]

high praise, thank you so much. Glad you like it!

[@brocluno01]

Good episode. Thanks for the info 😊 Now, have you "upgraded" the mechanical advance? Lots of these distributor bodies and the mechanical set to like 15*. But if you flip the weights over to the 20* side you can gain more advance as RPM rises. And still allow modest settings for idle initial 😁

[@dazecars]

good information thanks

[@P_RO_]

If you look closely you'll see those numbers stamped near the limiting slot. You'll also see a plastic tube on the arm to prevent metal-to-metal wear (which isn't really needed). Remove the tube for about a degree more movement. Back in the 'points' days there were several variations on this based on which exact engine it came on. This was the first "Ford trick" I learned waaaaay back then. The second was that some vacuum advances could be unscrewed and inside the spring was a phenolic limiting rod; by shortening it or blobbing JB weld to lengthen it your vacuum advance was also adjustable. Get anything you want from it at zero cost while the Chevy guys spend on advance kits 😁

[@dazecars]

good info, thanks

[@stevo196two9]

The only reason the Dura, Spark and the GMHEI had larger cap is to prevent crossfire inside the cap on higher energy ignitions now you just went back to create that problem with the higher spark. You’re gonna have to worry about crossfire inside the cap.

[@dazecars]

Several other people have stated the same theory BUT international used this cap on Duraspark distributors for over 20 years and aftermarket distributor caps like MSD are also smaller. Your crossfire inside the cap statement doesn’t hold up. It’s more likely they were trying to prevent crossfire outside the cap. Something a good set of wires can accomplish. Thanks for the comment.

[@dazecars]

There have been quite a few people that have seen this vido and said, "you will have crossfire inside the cap, that is why Ford went bigger" The conventional wisdom that Ford went to a bigger cap to avoid crossfire inside the cap is a myth and like all good myths it is based in a sound logical concept but I just discovered proof that it is in fact a myth. Yes the terminals are further apart and logically that would indicate less unwanted spark jumping because the spark has further to go, BUT I went out to my garage and compared the smaller cap rotor to the bigger cap rotor and the bigger cap rotor has a much bigger tip to account for it moving faster. I took the distance between the cap contacts, subtracted the width of the corresponding rotor tip width and divided by 2. The number was THE SAME. That means inside the cap, from a spark point of view there is no difference. From this information it is obvious Ford made the change to the bigger cap fore some reason OTHER than crossfire inside the cap. Not to mention that if crossfire inside the cap was an issue there would be 20 years of Internationals sitting on the side of the road. imagizer.imageshack.com/img924/6218/wbhQQU.jpg

[@ThomasLeonard454]

OMG Ford and their OEM parts system a hot rodders dream in the 60s and beyond. Thank you for sharing this Great tip.

[@dazecars]

My pleasure, thanks for watching!

[@JoshuaFletcher]

This is awesome!! Thanks for digging in and sharing thia

[@dazecars]

My Pleasure!

[@mikeelder6298]

In 1989 I went to buy a Ford truck and went to a dealership, and picked out a truck, did the loan application. It came back that I did not have any credit history. It wasn't bad credit, just no credit history. The salesman said, "You have NO business being on our lot. So get off our lot". Went to Chevrolet dealership the next day, picked out a truck and the next business day they called me and said, " Come get your truck off our lot". Been buying Chevrolets ever since.

[@dazecars]

interesting story thanks for the comment

[@kelvinhill9874]

I learned about this trick a couple of years ago. The FD311 rotor is the standard 57+ Ford V8 rotor used until the mid 70’s when the large cap Duraspark distributor came out

[@dazecars]

👍

[@sorshiaemms5959]

been using the old set up for years but didn t know this set up existed thanks will try it out

[@dazecars]

glad I could help

[@davidslocowb8717]

That's awesome info for the Ford guys wanting the more retro look.

[@dazecars]

I agree

[@MrFantasylover1]

Nice distributor info... it's crazy that it's not more popular knowledge!

[@dazecars]

It really is!

[@randydietel9708]

A big thanks for sharing as this was a problem I was trying to learn in order to work with my tunnel ram intake

[@dazecars]

Glad it helped

[@randydietel9708]

@@dazecars again thanks as this was a stump in my project trying to retain the factory distributor timing which worked best compared to after market gm copys

[@dazecars]

my pleasure

[@JimmyYahteez]

Another fantastic tip, thank you!

[@dazecars]

My pleasure!

[@jdau2b]

Dude !!! You just got this ol’ ford guy as a subscriber I could do nothing but giggle 😂when you pulled that adapter off cause ya taught an old dog a new trick!!!

[@dazecars]

happy to help, welcome to the channel

[@kevinjoyce4817]

I had a 78 jeep cj5 withe the 304 it had the small ford cap i changed it to the big ford setup with the big blue wires worked great

[@dazecars]

The big cap works well.

[@scottborkowski2411]

made the switch to small cap on my 79 cougar because my extender base was pretty worn out and moved to easily for my taste so used cap rotor and wires for a 75 mercury cougar with a 351W. worked beautifully.

[@dazecars]

even new the two piece design is sloppy. I think thats why Ford made the bottom piece bolt down when they came out with TFI

[@mikeberry2135]

Awesome! Thanks for sharing!

[@dazecars]

My pleasure

[@jonschick]

Excellent intel! Thank you.

[@dazecars]

Glad it was helpful!

[@hughwolfe8524]

Thank you 🙏 I didn't know this .I appreciate the information.

[@dazecars]

Glad it was helpful!

[@adrienst.raymond6801]

Dude I don’t even have a ford gasser and this is great to know! You’ve got my like and subscribe, good job bud👍

[@dazecars]

Thanks for the sub!

[@tools6106]

I saw a red lid like these in the 90’s I believe it may have been a Mallory product. It had all the fancy stuff, copper electrode connectors. It was very cool, I always thought this was ultra high end race stuff! Cool link for those of us in the normal build price range!

[@dazecars]

glad I could help!!!

[@Hoghaw]

Anything that will shorten the length of the Ford distributor, will help with the installation of a roots type supercharger. Great information!

[@dazecars]

Glad I could help

[@victoryfirst2878]

Thanks for the information fella. Now I know too.

[@dazecars]

No problem 👍

[@raginroadrunner]

The big cap stopped spark scatter and Ozone buildup. Works perfect.

[@dazecars]

Ozone build up is eliminated by venting the cap and the bigger cap is vented so I will give you that. As to to spark skater that statement is a logical conclusion based on limited information. Lots of people keep saying that or something similar because it makes logical sense but that logic COMPLETELY IGNORES the number of Durasparks systems running this very cap or the female/points type cap from the factory. While crossfire/tracing is a potential issue with any cap especially as RPM goes up, if that was the reason, it was to compensate for some cost saving thing like cheaper spark plug wires or even more likely to compensate for high resistance wires that had an emissions benefit. Duraspark was used on tones of AMC, International, Jeep, and even some Chrysler vehicles and NONE of them use a bigger cap, only Ford. Most use the female type points cap. So while crossfire is a possible reason I don't buy it as MSD and Pertronics distributors are hotter and use a cap of similar size and design to the cap featured on this video. Ultimately this is ALL speculation however many view the crossfire theory as gospel. I have had a tone of people say they have been running this cap for years, I have had a tone of people say as you did "bigger is to avoid crossfire" but not one person said I tried the smaller cap, had crossfire and had to go back. If the bigger cap was truly better high energy aftermarket systems like PerTronix and MSD would use this bigger cap, but they don’t. Their caps are no bigger than the international cap featured in this video. Regardless of why Ford did it, International ran this cap using all duraspark parts on almost everything V8 for years and AMC, Jeep and Chrysler used the duraspark with the points cap so it clearly works and had crossfire or tracing been problematic they would have done what was cheap and easy and switched to the bigger cap Ford was already using.

[@williamschubert3929]

I used the same distributor on my 88 notchback 306. Easily wired it to my 6AL MSD with rev limiter and tach.

[@dazecars]

they work well

[@dkdj5]

Great set up. If clearance isn't an issue, I use the GM style HEI. Yes they make distributors that fit many Fords.

[@dazecars]

There are those that really like the HEI. I am not a fan but that is just my opinion

[@terrycarter8929]

Well thats good info. I never would have thought to look for a International for that cap..... thanx

[@dazecars]

exactly, that is why it is the "best kept secret" no one is asking the question. I only asked because I didn't have room for the bigger cap on my Frankenstein EFI project

[@jefferypitts343]

I've had this setup for 35 years, I used a duraspark box off a lincoln, I recommend this to any ford guy, yes adding an msd would be good, I like simple.

[@dazecars]

For me this distributor and an MSD box in place of the ford unit is the perfect combo

[@bobbusanovitch913]

THANKS! Nice job, now I will have more room in my 302 kit car!!

[@dazecars]

Glad to help

[@christophereaves862]

Thanks Daze Cars, I have a 77 f150 I’m redoing. I didn’t know this trick

[@dazecars]

Glad I could help

[@paulcasarez404]

My dad was a Ford and Chrysler gear head from the early 1950s he always knew stuff similar to this and he would rework Ford cylinder heads I have the heads and distributor he reworked on our 65 mustang and man I tell you his setup is freaking killer I been running the mustang since 1995 and here in 2024 it still runs strong as f

[@dazecars]

There is a lot of old school wisdom out there

[@g50stang72]

No way! That’s an awesome tip. I love it.

[@dazecars]

Glad it was helpful!

[@MegaScott]

Ford blue has been running in my veins since 12YO. I knew this trick, and a whole bunch more about these Distributor's, including the late model TFI Dizzys. One of my first cars was a '68 XR7 Cougar that a guy wanted to trade me for a POS 52 Chevy I had just got running. He had just "Tuned up" the car and it never ran right after that...turns out, firing order was 180 out, but that lead me right to the rotor...The parts store gave him a Dodge Rotor! In case you're wondering,...yeah, the key in rotor is exactly opposite of the Ford Rotor key, making it 180 out!...Swapped the rotor with one I had in my box of good parts, smashed the Dodge rotor with a hammer and that Cougar was a great runner!

[@dazecars]

It is very interesting sll the different interchange out there.

[@FordMonsterTruck]

Thats awesome! Thank you for the information!

[@dazecars]

My pleasure!

[@308dad8]

Yep points are good, just don’t leave ignition on if you’re not running the engine, and use condenser and points for the voltage you’re running.

[@dazecars]

I agree points are a viable option.

[@akh21849]

I have a points system in my old ford and love it, but may consider it

[@dazecars]

when set up correctly and maintained points are an excellent ignition system. For me I was going to run an MSD box either way so it made a lot more sense to drive it with a magnetic pickup for accuracy.

[@morgansword]

I actually stumbled on to this many many years ago and working with just what I had on hand... did this. Biggest difference was a MSD versus a system that had different types of colored plugs that you matched the that distributor. They would go bad and so with a new box, good to go. Then I found out that when the next one went bad, I could just plug in the old one and nine out of ten, for some reason it worked again. I just left both under the hood and could make it home. Now I like points for sure as they put a lot of my cars on the road for a long time but you add more fuel for what ever reason you think you needed it.... a duraspark ignition is the only way to get a good fire out of sub standard plugs.

[@dazecars]

That is the number one complaint with the Ford module is they go bad. I eliminated my module all together and use the distributor to trigger my MSD box.

[@thomastucker5998]

This may be the solution I am looking for. I have installed a 460 into a ‘65 Comet. I have a drop center base for my air filter because I don’t want to cut a hole in my hood. I want to run an electronic distributor but was concerned about clearance. Thanks for the info!

[@dazecars]

Glad I could help

[@Z-Bart]

That 460 should wake up The Comet. Wowzer.

[@dazecars]

👍

[@eddymetal84]

This is awesome, Thanks for video!

[@dazecars]

My pleasure!

[@jeremiahfiek5495]

@dazecars I've got one for ya. So you can convert a fuel injected ford engine to carburated and get a specific TPS sensor (cant remember the #) and mount in on the throttle shaft of the carb and you leave all the rest of the sensors and ignition hooked up as it was. Hook the MAP sensor up to manifold vac. Etc.... by doing that you can still run your E4OD trans AND you still have the computer controlled self learning ignition system with a CARBURATOR Valuable information considering the higher flow EFI intakes for ford trucks are ridiculously expensive. So are the trans controllers.

[@dazecars]

sounds interesting

[@jeremiahfiek5495]

@@dazecars thought you might like that idea since you frankensteined that one

[@dazecars]

👍

[@cliffhaupt5413]

Great info buddy thanks.

[@dazecars]

My pleasure

[@fastst1]

I converted a 351cj to duraspark from points I was stunned at how hot that spark was even compared to big yellow coil. Ford e-mag coil would really fry your biscuits if you got on the dumb end.

[@dazecars]

it is for sure a good ignition system

[@danielmcqueen1024]

As an Ole Ford Guy, I always swapped out to the bigger cap to help with cross fire at high RPMs! Plus I really liked the look on my old 351Windsor and 429 Lima motors :)

[@dazecars]

Did you make the swap because smaller caps were actually suffering from crossfire at higher RPM or as preventative maintenance to avoid the potential problem?

[@danielmcqueen1024]

@@dazecars I was having cross fire issues at the track, getting cross fire at starting about 5800 rpms... the Mushroom cap fixed that issue... The problem only seemed to show up when I changed from the 302 Boss motor to the 351 Street Boss. Not sure it was a cam to timing issue but the big cap fixed that and stayed in the 11.4 quarters at that :)

[@dazecars]

Thanks for the info. Your application (high RPM for sustained periods) is one area where the big cap makes a lot more sense.

[@michaelleahey2759]

That is pretty cool, thanks for sharing.

[@dazecars]

Thanks for watching!

[@arniesantacruz4513]

Nice some of this i deas definitely need to put it my head thank you so much 👍🏻👍🏻👍🏻👍🏻

[@dazecars]

No problem 👍

[@ScroatBagGarage]

did this back in the mid 80's on a 351w / 4cyl swap. That pancake duraspark top had to go. Thanks for showing the part number, it's been way too long and I forgot all about it.

[@dazecars]

I think it was more widely known in the 80s but the info has become more obscure.

[@2nd66tube2]

both styles came in the box when I bought my last DuraSpark II distributor from AZ

[@dazecars]

good to know

[@v1-vr-rotatev2-vy_vx31]

Back in the day champion spark plug, did some serious distributor work... They took the Ford distributor weight system, integrated with general motors externally adjustable duel points and sold the idea to Excell... A friend had MSD electronic distributor in perfect working order, in his Fuel Altered 351 cu in.. running Elevens 1/4 mile, swap it out with an Excel dual point Distributer and ran in the 9 second s in 1/4 mile...

[@dazecars]

Thanks for the info

[@CK-mf6du]

Good to know! Possible you overlooked the phase of the roter! The length of the arm on vacuum advance is different between early and late style caps. They swap, but your rotor and lug alignment can get messed up. I'd check where the international cap comes out.

[@dazecars]

Thanks for pointing that out. This cap is a direct replacement for the later stile cap. Everything is positioned the exact same only smaller.

[@CK-mf6du]

@@dazecars very good to know!

[@dazecars]

happy to help

[@junkyardwizard9092]

I used this back IH cap in about 2005/2006 for clearance in a Tunnel Rammed SBF 302 with dual Predators carbs

[@dazecars]

Its amazing how much room the smaller cap gives you

[@williamjesse8357]

Thank you for sharing this video and awesome information as am a old Ford guy !

[@dazecars]

My pleasure!!

[@ricksgt2012]

Amazing info thanks.

[@dazecars]

Glad it was helpful!

[@AA-tb4ff]

I remember putting the bigger ford cap on my 360 amc because i heard the wires were further apart and you would get less cross firing between the wires with it compared to the small amc cap

[@dazecars]

"you heard it was better" but did you find it made any difference, where you actually having any issues with the smaller cap? Each system has lots of different components and some may find there is an issue, others may find there is not, either way international ran this cap for 20 years so I'm thinking it is not a problem in most cases and not the issue some are making it out to be. Thanks for the comment.

[@AA-tb4ff]

@@dazecars I never had a problem with the small cap. I think I read the tip in jp magazine. I think cross firing becomes more of an issue on the small cap when you have a really hot coil

[@chuckm5923]

If you don’t need the smaller cap for clearance issues run the big one. The hotter e core coils and CDI boxes are shooting out lighting bolts! Get the big cap with brass contacts.

[@dazecars]

Can you prove it's "better", it's all theories and conjecture. Only the Ford engineers in the 70s really know. If the bigger cap was truly better high energy aftermarket systems like PerTronix and MSD would use this bigger cap, but they don’t. Their caps are no bigger than the international cap featured in this video. The prevailing "wisdom" as to why Ford made the switch was to avoid crossfire but if the duraspark suffered from crossfire there was some other factor like cheaper spark plug wires or other inferior materials they were compensating for as aftermarket systems don't have this problem and they run even hotter. Another theory is the bigger rotor allows for a longer spark duration for emissions. That is plausible but given the circumference os bigger the rotor is traveling faster so I not sure I agree with that one either. Regardless of why Ford did it, International ran this cap using all duraspark parts on almost everything V8 for 20 years so it clearly works and had it been problematic they would have done what was cheap and easy and switched to what Ford was already using.@@chuckm5923

[@hotrodray6802]

​@@chuckm5923 Yes, but nothing compared to an MSD box. It's scary the first time you see an MSD 6 jumping a ONE INCH gap.

[@chucksgarage7165]

Rockauto has the cap for $22. Thanks for sharing!

[@dazecars]

Yes but how much is the shipping. Rick auto has outstanding prices UNTIL you add the shipping. 😁

[@606garage4]

Great video!! Much appreciated!!

[@dazecars]

Glad it was helpful!

[@frederickbooth7970]

Even though all my old trucks are GM this was very interesting simplification of a Ford distributor. Only our old tractors are Fords. They are all 8n`s, 2 with loaders.

[@dazecars]

glad you liked it, thanks for the comment

[@charlesangell_bulmtl]

Had an undetected booster leak on my'84 F250...the MSD and a cheap Cardone '78 4.9L dist. got it started ...👍 I ordered the big cap & got some cheap non-vent MSD caps on eBay as replacements ...

[@dazecars]

Thanks for sharing

[@rebekahfrench5747]

30 yrs ago modified a cleveland distributor and fitted the trusty mopar electronic internals to get more precise spark works a treat and still going.. 👍

[@dazecars]

sounds interesting

[@rebekahfrench5747]

@@dazecars just have to overcome rotational direction difference and job works a sweet treat.. killed two to make one a winner.. the joys of the pursuit to make horsepower more reliable..👍

[@rebekahfrench5747]

@@dazecars last dyno sesh spark was above 80kv small cap and negligable cross firing so it was a win win..

[@kblackav8or]

a 460 duraspark distributor is identical to the Cleveland distributor and drops right in and works great with no fangling.

[@rebekahfrench5747]

@@kblackav8or 460s are quite rare here in Australia..

[@williameltringham7559]

Probably won't ever use this but it got me to subscribe

[@dazecars]

I appreciate the subscription but I would much rather be producing something you can use 😁 Check out my 393W build playlist or my Frankenstein EFI playlist. Fun projects that may be more "usable"?

[@williameltringham7559]

@@dazecars I will watch it. I have been a engine builder for 43 years, built and raced Ford mostly but your videos proves you can always learn something.

[@dazecars]

@@williameltringham7559 maybe you shouldn’t watch it then 🤣🤣🤣 I am just a hobbies and not an engine builder. Probably wouldn’t get much from it. If you do watch and see any errors let me know. I want to put out accurate information.

[@reddelta3898]

Panteras have little room to spare for the distributor of a 351C in a mid-engine layout. The front mounted distributor is great in a Mustang but not in a Pantera. This is great info! Thanks for sharing.

[@dazecars]

Glad I was able to help!!

[@rodneysteffen6376]

True. I run the small cap duraspark on my Pantera. Simple, reliable, inexpensive and readily available.

[@ProjectFairmont]

True that. I have a replica GT40; CAV GT. It had a crap small cap w/external HEI module dizzy. After fighting inconsistent spark, I changed it out with a Crab cap MSD dizzy (male ends on a horizontal plane vs vertical) and Mallory ignition box. Nice piece. Yea, the front Ford location is not ideal for mid engine. However, it’s a clean appearance once the fiddling is complete and in my case does not interfere with the 180 degree exhaust running above the backside of the engine 👍🏼

[@dazecars]

lots of people asking about a crab cap that fits stock distributor but haven't found one yet.

[@rustybritches6747]

Speedmaster pro billet dizi, (small cap) used 6al and a blaster SS coil! More $ and more wiring but what a great setup for around or less than $400. on a budget performance build its very versatile and tunable. The digital 6al is even better because it has an adjustable rev limiter.

[@dazecars]

I am running the exact same setup except for the stock distributor and a 6A box rather than 6AL. The MSD box is easily driven by the factory Ford distributor.

[@firepinto]

That is awesome!

[@dazecars]

Thanks!! I was very pleased and surprised to find this option.

[@joesolley7407]

I had an 86 F 150, 300 - six. The parts book showed I was supposed to have the bigger cap as standard, but it was equipped with the smaller one. They said it was an option for that year.

[@dazecars]

I bet however it was a female cap?

[@joesolley7407]

Don't remember, been too long since I owned the truck. Had to ask for an 85 cap instead of 86.@@dazecars

[@dazecars]

👍

[@Adrenacyde]

Outstanding!

[@dazecars]

Glad you like it!

[@USMC0311CplJackson]

Solid gold. Saving this for later reference.

[@dazecars]

glad I could help

[@simon_hawk5758]

Thats fantastic! Thanks!

[@dazecars]

Glad you like it!

[@johngranato2673]

I run an original FOMOCO Distributor with a Pertronix trigger to my old (USA-Made) MSD box. My only gripe? I wish the distributor weights were up high, like the 1973 Buick I had when I was a kid.

[@dazecars]

At one time you could get an aftermarket tuning kit with different weights. Not sure if they are sill available

[@johngranato2673]

@@dazecars I know. I'm referring to the location of the weights.

[@dazecars]

sorry, my bad@@johngranato2673

[@eliteman7685]

I ran a duraspark unit for years. Swapped in a '77 400 duraspark distributor and I used the smaller cap on mine for better air cleaner clearance. Found the AMC cap like you pointed out. MSD Streetfire built as needed plug wires, with a 1976 red wire duraspark high output brain box. Ran it on my car for years. I recently upgraded to a MSD pro billet unit and it's damn near a copy of the duraspark setup for the internals. One thing I found the MSD is a pain, it pulls in timing WAY too rapidly and needs different bushings. The Durasparks don't pull in at the excessive rate the MSD unit does, even with tweaks and different springs. You can get bushings to like from an outfit but found sometimes, the Duraspark units can take up to 60HP with no issues based on experience in the 351C community. I honestly only swapped to the MSD pro billet due to a 393 stroker Cleveland I took in trade for money owed to me, so I went *shrug* and decided to run the MSD for a while.

[@dazecars]

Its an outstanding distributor!!! some might even call it the "gold standard" 😁😁

[@eliteman7685]

@@dazecars key things to remember, Duraspark units are typically shown good to around 600HP. Biggest issue is making sure the roll pin is secure. 351C community typically would run a double pin some times and green loctite to secure the distributor gear on high volume pump applications. This is from my notes regarding the 351C/Torino communities) (1976 red wire California emissions Duraspark units, as noted in Pantera forums)

[@dazecars]

good info, thanks

[@Glens1965]

Learn something new everyday.

[@dazecars]

It's amazing how many gems there are out there and we don't even know what we don't know.

[@wayneprater8960]

I learned that the points, Duraspark and TFI were the same diameter due to a late night wrenching and a dropped points distributor cap I pulled a TFI and wires off the shelf on a hunch after I realized I was at a point of stop and wait for a parts store or try it and wire it to the non-HO 302 firing order my buddy Steve said I was a super genius. Lol I was just a blind man grasping at straws.

[@dazecars]

so the duraspark and TFI use the same top cap but the adapter pice is different. The TFI mid piece screws down where as the duraspark piece clips down. The points setup is the same as the mid piece on the duraspark. In other words the points and duraspark are completely interchangeable but only the cap is interchangeable wit the TFI

[@TX_Blake]

Love this!

[@dazecars]

Glad to hear it… please tell your friends 😁

[@DanEBoyd]

Never heard of this till now! Would've saved me from buying new wires when I put Duraspark on my old '68 Cougar,

[@dazecars]

I have been getting that a lot

[@philmorrissette]

Great Tip !

[@dazecars]

Glad it was helpful!

[@glastornjet73]

Great info but i would keep the large cap wherever possible it helps with crossfire issues. Also you dont need an msd box to not use the duraspark box. You can also use it to trigger probably the most widely produced and most reliable electronic ignition ever produced the gm hei. Its simple get you a regular hei 4 wire ignition module an ignition coil from a 94-96 lt1 and a heat sink and coil mount from an lt1 bolt down the entire system run 4 wires and bam

[@dazecars]

My problem with the HEI module is the spark tapers as RPM goes up. I use the MSD because of the performance inhancement of multaple spark and a hotter spark. Nice thing is with the MSD box I don't need an HEI module or a Ford Duraspark module. As to the crossfire, that is internet "wisdom". Lots of people keep saying that because it makes logical sense but that logic completely ignores the number of small cap distributors out there. The truth is we really don't know why Ford went with the bigger cap. There are three prevailing theories: crossfire inside the cap, crossfire outside the cap, and to increase spark duration for better emissions. While crossfire is a potential issue with any cap especially as RPM goes up, if that was the reason, it was to compensate for some cost saving thing like cheaper spark plug wires. Duraspark was used on tones of AMC, International, and even some Chrysler vehicles and none of them use a bigger cap, only Ford. Most use the female type points cap. So while crossfire is a possible reason I don't buy it as MSD and Pertronics distributors are hotter and use a cap of similar size to this smaller one. Like the crossfire theory the logic of the "longer spark" theory seams to totally make sense when you look at the tip of the rotors and see the bigger rotor tip is almost twice as wide, but the terminals inside the bigger cap are smaller and the rotor tip for the bigger cap has to move faster because it has further to travel so I don't buy into that either. Ultimately this is ALL speculation however many view the crossfire theory as gospel. I have had a tone of people say they have been running this cap for years, I have had a tone of people say as you did "bigger is to avoid crossfire" but not one person said I tried it, had crossfire and had to go back. I would love to talk to a 70s Ford engineer to find out for sure. The one thing I believe firmly is for Ford to be the only manufacturer to do it, it was likely somehow a cost saving measure somewher in the system. And for all the other manufactures to not do it crossfire is not the reason.

[@glastornjet73]

@@dazecars if you actually drive your car you better have a spare msd in the trunk or you will eventually need a tow home. They are JUNK! I agree an hei module is not the best for performance but lets be honest you Dont have an engine that it will make a difference on. 90% of people dont. And as for the large cap and crossfiring issues you say dont exist... there is a reason msd as well as mallory moroso and every other company uses large caps on their magnetos and higher end race distributors. With very high spark energy or high advance settings there is more room between the terminals to prevent cross fireing gm started the large cap on the hei and everyone else followed suit because it works end of story! Now if you have clearance issues i understand wanting a smaller cap and your amc cap with “hei terminals” is a great find but if clearance is not an issue a large cap is superior in every way every time.

[@glastornjet73]

@@dazecars and I can tell you exactly the reason they went to the larger Has nothing to do with anything you said! With a strictly mechanical advance distributor you didn’t need the large cap because there was only so much advance to be had when Ford went to the magnetic pick up with electronica spark advance in the box and no mechanical advance in the distributor they went to that larger Because because they were using more advanced than mechanical advance would allow thus needing more room for the rotor to be able to direct the spark to the desired terminal when running 20 degrees of Electronica Vance without an advance mechanism in the distributor to compensate for it

[@dazecars]

That may be your opinion on MSD but that is not my experience. Daily drivers with tons of miles no issue 20 years. As to the crossfire I'm not saying it doesn't exist, yes extreme situations will require a bigger cap but a normal street engine is not going to turn the kind of RPM that leads to crossfire. Again 20 years on AMC, international, and jeep. Not to mention all the people running this exact cap on the duraspark and then all the people that converted their duraspark to a female cap. Millions of cars with the smaller cap of one form or another. Is crossfire a potential issue with any distributor yes but if it was the issue the internet theorists make it out to be ALL the other manufacturers would be running the bigger cap same as Ford. As far as GM and and their bigger cap design again it's all speculation. More than likely the bigger size was to accommodate the coil.@@glastornjet73

[@dazecars]

That may be the best theory I have hard so far in regards to a TFI but not a Duraspark (unless I'm missing something) First you are still completely ignoring all the other makes and models that used the complete Duraspark system with module and distributor that run the smaller cap. Second I don't see how advance can electronically increase with a duraspark (this may be where I'm missing something please educate me if I am wrong) . If the module fires earlier the rotor still needs to be in proximity to the terminal so advance is still controlled by the mechanical weights , vacuum advance and initial timing. It's not like the TFI where the computer actually adjusts the timing inside the distributor. In that case I can see where a bigger distributor could be better. But MSD has their dual sink distributor where timing is computer controlled and the cap is small like the international cap so if for ford the bigger cap was needed to avoid crossfire it was likely due to going cheap somewhere else. I do appreciate all your comments. I would love to know the actual answer. All of these design choices by manufactures were likely for several reasons and part of a complete system. That is why there is no perfect answer because we are trying to logic it out to solve only one potential problem. @@glastornjet73