Comparing Junkyard GT40 GT40P Stock E7 Cylinder Heads / Everything U NEED 2 Know - Fox body Mustang

[@arkhsm]

Did you know that my Factory GT40p heads were Factory modified by Ford Australia, with 1.94 intake, 1.54 exhaust valves ! The whole engine was hand built by one man, taking one complete day to assemble, and they also received a set of Yella Terra roller rockers, plus a mild port matching, and custom 70mm throttle body. They also got a factory set of headers, with a complete dual exhaust system. Only late 2001 to early 2002 Falcon XR8 got this 295hp beauty !! The TOP DOG T series version of this engine even has a 3.4 inch stroker crank, making it 342 ci and 335hp !!!

[@KASLCustoms]

No way!? Thats awesome!

[@SassyXR6007]

​@@KASLCustoms yes way 😊

[@luisfdoocastorjames]

I didn't knew there was a 4door manual sbf EFI, Aus really knows how to make cool cars

[@frederickhairston3823]

Just installed gt40p on 1993 fox 5.0 love them ford tough.

[@KASLCustoms]

Right on!!

[@danmallery9142]

GT40 heads are the first "aftermarket" heads that I ever bought. I got them for my 71 Bronco back around 92 or 93? Can't remember exactly. I had some mild porting done and added some Harland Sharp roller rockers. Not many other options back then, plus, I wanted to stick with Ford parts. They worked good. No comparison to modern aluminum heads that we have today but those were just a dream back then.

[@KASLCustoms]

Yessir I agree 👍

[@midnight347]

Big dog does some badass porting nowadays that makes these heads flow better than out the box aluminim heads

[@foxfordcatguy2283]

The GT40 & GT40p also have "GT" or "GTP" cast between the #1 sparkplug (#8 on driver's side) & the end headbolt. The GT40p also has a "P" right above there on the little "ledge" by the corner of the valve cover. Maybe not all, but mine do & these markings are also described in the "Ford High Performance Parts Interchange" book & the "Muscle Mustang & Fast Fords" January '98 issue "Exploring For More" article starting on page #222. The GT40's were used on '96 to mid-'97 Explorers. The GT40p was used from mid-'97 to '01. The GT40p (58-61cc) has a SMALLER combustion chamber than both the E7 (62-65cc) & the GT40 (F1ZE 63-66cc, F3ZE 60-63cc, F4ZE 63-66cc). [This info is also in the previously mentioned book & article.]

[@angeljose6261]

I just picked up some gt's yesterday at a wrecking yard and you're right

[@OurCabinInThewoods]

Great info on these heads Thanks. I have a 97 Mountaineer with GT40p heads i installed Torque Monster Headers and Gibson performance exhaust system. I don't have a problem getting to my plugs. Now i did add Spark Plug Wire Boots Heat Shield Protector Sleeves. They have been on the truck for 160K with no problems. I love the torque it has. Thanks for sharing this video.

[@KASLCustoms]

Very nice! You're welcome!

[@MrJak427]

I’ve driven a few late model falcons in Australia and the explorer 5.0 was heaps more torquey in the low rpm’s compared to the std 5.0 with e7’s so it makes perfect sense to put an engine with more torque into a large heavy SUV they weren’t race car parts just the next evolution of a stock casting

[@NGG1983]

I suspect that Ford put the GT40 and Gt40p heads on Explorers and Mountaineers simply because they're more efficient and make more power. Remember those trucks got a low rpm torque truck camshaft in them so even with those higher performance parts they make like 205HP. If they had E7 heads and a smaller port intake they would make even less power and customers would likely be unimpressed with the power you'd expect in a V8 option truck. Its a massively heavy all-wheel drive vehicle too so it would simply be underpowered with E7 heads

[@randytrivitt6539]

Absolutely correct the explorers and mountaineers wait around 6800 lb!! Compared to the mustangs 3200 lb!! So of course they're going to put high performance heads on heavier vehicles or at least stock racing vehicles!! Like the mustang cobras and the GTS mustangs!! 100% agree... 💯👍👍🤷🤯🤯🤦😁👍👍🙌

[@thacutoff6226]

All your points are right, however Ford is just cheap they plenty left over from mustangs ……. They just used them out in 96/97 explorers 3 bars (Eddie bauers edition) then they shift to p style

[@foxfordcatguy2283]

​@@thacutoff6226 The GT40's only came in Mustang Cobras. They also have dates codes on them showing they were made after the 5.0 was discontinued in the Mustang. The GT40P never came in ANY Mustang.

[@thacutoff6226]

@@foxfordcatguy2283 gt40 3 bar heads came on mustang cobras except that they are on 96/97 ford explorers Eddie bauers and Mercury mountaineers ford used remaining leftover discontinued 5.0 stuff I.e explorer intakes (just basically cobra intakes). Gt40p heads have 4 bars stamped, and are different the main issue is headers/spark plugs

[@onescaryapothiconboi7475]

@@randytrivitt6539 I think I lost brain cells reading your post. These Explorers topped out at 4,200 lbs. Only 1,000 heavier than the SN95.

[@Canadiancigarguy]

I’m in the middle of a 68 mustang restoration, my 289 needs a rebuilt but I’m going to put a 302 with gt40 heads in its place … thanks for the info that helped with selecting headers

[@KASLCustoms]

Right on! Glad I could help sir!

[@CoffeeCaffiend82]

I used to have GT40p heads with a E303 cam and gt40 intake with 1.7 rockers on my 88 lx👌🏽 ran 12.9s all day on 93

[@KASLCustoms]

Nice!

[@troyterry8048]

Loved the information, keep the content coming. Here in Australia I had an AU XR8 falcon with a 302 windsor with factory gt40p heads, factory roller rockers, different cam specifications to the standard 5litre and they produced 220kw from the factory. It was a great little engine

[@KASLCustoms]

Awesome thank you so much!!! Glad you like the video. I will definitely have more coming on this in the near future. Wow that sounds like an great little combo!

[@ogsuperflygarage]

This is a great video comparison and explanation! Like how you kept the explanation simple and in layman’s terms. 💯 The podcast is really cool and informative. I appreciate the VERY relaxed nature of it. 💯👊🏾

[@KASLCustoms]

Thx so much buddy!!!

[@robviousobviously5757]

347 full roller with GT40P heads.. moderate cam & 4 barrel Holley in a 67 Fastback Mustang backed with a Tremec 3550 World class 5 speed, 9 inch 3.70 Detroit Locker... works great.. about 400hp & 375 ft# of torque... exciting

[@autofox5.067]

I was at Foxtoberfest this year and I believe I was parked next to the guy that won the spot you gave away. I won my spot from Neomustangs. I look forward to being there this year as well!

[@KASLCustoms]

That’s awesome buddy!!! Same here

[@kimcokevin]

Spark plugs clear on BBK equal length headers on P heads. I put 90’s on all 8 spark plug wires for my ocd sake. They are accessible with a cut down plug socket, but a pain. Definitely a job to do when it’s cold. Best flowing factory Ford small block head ever, that’s the only reason why I went with them. If I could ever source the Ford Racing P specific headers then I would definitely purchase.

[@KASLCustoms]

Thx for the Info my friend!

[@terrygrover6440]

Out of all the ford heads I have to say that the E7s will run with any head if you do the right things to them , our car the green gangster runs 10s on motor with ported E7s and a stock short block and 9s with a 150 shot the car is on KZbin if you want to check it out under grover boys racing , appreciate all the foxbody content you share with us 😀

[@KASLCustoms]

Wow that’s fast!!! Ok I’ll check it out thanks buddy!

[@Backfire10]

Agreed. You have to optimize the chambers and clean them exhast port up.. for sure.

[@hotrodray6802]

Dad is a very good porter and youz guyz know your stuff.👍

[@ericmesa949]

The explorers in 1995 and 1996 were first introduced as state trooper,game warden and forest service Rangers vehicles with cobra style v8 GT40 3bar and AWD for the off road, dirt road and snow trail. In Canada and USA

[@hotrodray6802]

😎🔔 David Freiberger did dyno tests on headers about making dents into the tubes. Virtually insignificant until they're completely mangled. Plug clearance can be grained by using a 3/4" socket and hammer, maybe torch heat. 90* boots are no big deal either. JMO.😎

[@Frankie4231]

I got mine at the machine shop now, thanks for all the videos on this topic pretty pumped about getting everything bolted up

[@KASLCustoms]

Right on! Thx buddy!

[@brycebeamer2600]

Great clip 👌 I enjoyed the insight about all those different heads. Keep up the the good work 💯

[@KASLCustoms]

Thx buddy will do 🫡👊

[@jimberry1227]

Great information Thanks for sharing your knowledge ✅

[@KASLCustoms]

Thank you!

[@scottkinsella190]

Hey Gary , awesome video. GT40 parts so hard to find now.

[@KASLCustoms]

Thx buddy! Yes it’s true

[@anthonyanderson464]

The explorer and mountaineer was the last platform from 97 to 02 to have the 5.0 pushrod motor.

[@4rered860]

I have a set of 3 bar aluminum GT40 heads, the only thing I found were these heads were built by ford for experimenting, but later trash this project (ordered to recycle these heads, but not all were sent to the crusher) and came out with the GT40X

[@KASLCustoms]

That’s awesome!

[@4rered860]

@@KASLCustoms thanks, I was wondering if you know anything about them or heard of them, I was only able to get very little information about them through the website

[@KASLCustoms]

Sorry I wish I did but I’ve never seen a set myself

[@williamcharles9480]

KASL Customs, I appreciate the video. I read the other day that the 3-bar GT40 heads that were fitted onto the 93-94 Cobra had a smaller combustion chamber. Something like about 60cc. The GT40 heads that went to other vehicles other than the "Cobra" carried a slightly larger combustion chamber in the range of 64-65cc. The Cobra also had the Crane manufactured, 1.7:1 Ford Spec. roller rockers rather than the 1.6:1 non-roller as used in the 5.0 HO. The source also stated that Ford took the standard GT40 casting and shaved .010 inch off the deck surface to achieve the 60cc chamber. I guess I need to check the chamber size on the 3-bar set that I got on the "GT40, Cobra" crate engine that I bought from Ford Racing back in 1994. Another curious thing that I found is that Ford Racing didn't include the 1.7 roller rockers on that Cobra crate engine either. I had to buy my own. One more thing to mention is that the GT40 3-bar set that I have has the thermactor ports, but doesn't have those restrictive humps in the exhaust ports, like the E7 castings. The ports are there, though, if you had to use them. If you need to plug the inlets for the thermactor, you can buy the plugs or use a 5/8"-11 set-screw (Stainless Preferred). This is a straight thread with a female Allen hex on one end and a tapered end on the other. These are NOT a taper thread pipe plug. Lastly, the GT40P heads don't have the thermactor ports at all.

[@KASLCustoms]

Great info!!! Thanks so much for sharing

[@stephenroberts7816]

Great stuff! I love the old school builds from back in the day! The 3 bar heads are my favorite of the iron heads but they are no where near those AFR 165s you got on your coupe! Man I want to come down to NC to have a beer with you!

[@KASLCustoms]

Thx buddy! Same here. I love this old iron. You need to get off your butt and make the trip!!! 😎🍻🍻🍻

[@midnight347]

They can be with big dogs porting he makes em outflow most out the box aluminum heads. Obviously ported vs ported the afr will win but the right porting can make these heads perform killer. Def worth it if you already have these heads. They will port match a gt40/cobra style intake to it as well. That with a custom cam will yield surprising results. People underestimate what can be done with these heads. Even the stock e7 heads with the right port work.

[@gpt5002]

Everyone knocks the smaller exhaust valve. It’s bc the compression is higher so it burns fuel more effectively so they don’t have to get rid of more excess gasses. Gasses are heavier than air. Idk if that makes sense but it does to me.

[@hotrodray6802]

Better exhaust port.

[@aussi3212]

Here in Australia in the early 2000s gt40p were thought of as topfuel heads 😂

[@KASLCustoms]

LOL thats awesome!

[@foxfordcatguy2283]

The GT40 head was not "introduced" on the 1993 Cobra, they were already available from Ford Racing (Ford Motorsport SVO as it was called at the time.) According to "The Official Ford Mustang 5.0 Technical Reference & Performance Handbook" by Al Kirschenbaum, they were originally developed for a planned 1989 anniversary model that obviously never happened. So they then went in the Ford Motorsport SVO Catalog. The tubular GT40 also was available from Ford Motorsport BEFORE it appeared on the 1st Gen Lightning. I still have my 1992 Ford Motorsport SVO catalog with both the GT40 heads & intake available in it.

[@KASLCustoms]

Too cool 👌

[@72442conv]

@@KASLCustoms I had a speed shop in the late 80's early 90's and a ton of my customers were 5.0 Mustang guys. Sold tons of 5.0 Mustang parts. The Ford Motorsport "World Class" T-5 was one of the best sellers, if you street raced your 5.0, then you would eventually buy one, or two, or three... The Gt40 heads and the GT40 tubular intake were available in the Ford Motorsport Catalog way before they were on any production car, sold quite a few of them. When it came to cylinder heads the hot ticket were not the GT40 heads but the Dart cast iron heads. The Dart heads had 2.02 and 1.60 valves and 200cc intake ports.

[@hotrodray6802]

​@@72442conv Yes

[@juanf4739]

I believe that these parts were used because they produce more power with better emissions. That’s too many intakes and heads to have been over produced. Great content keep it coming, thank you.

[@KASLCustoms]

Thank you - will do!

[@steved479]

I thought the explorers got the upgraded heads as the 5.0 got older and they had to add emissions gear which robbed power; so, they threw the better heads on to make up for it. IIRC, the power numbers stayed pretty much the same through the explorer run. Jeep did the same thing with the 4.0l, if you throw a later model 4.0L intake on an older HO engine you'd gain 25ish HP, even though they both made the same power numbers from the factory (92 vs 02 for example)

[@johnjones928]

The p's had smaller exhaust valves for two reasons, first the original 40's had hardened, pressed in seats on the exhaust side to prevent valve recession, as they were meant for use on a lower sales volume unit Ford rolled the extra cost into the Cobra package. For the p head they used the same induction hardening as the E7's to save cost on the higher sale volume part. The second reason is the p was given an exhaust port that actually flowed marginally better than the original 40 so the bigger valve wasn't needed to meet the engineers goal. The truth is the p was never built to make more power, it was made to burn cleaner and be more efficient than the E7, the engine guys realized the 40 package in the Cobra has less emissions than the stock gt so they based the new head on the 40. Ford was worried their increased SUV sales would hurt their EPA CAFE numbers, that was the reason for the repositioned spark plug as well.

[@KASLCustoms]

Wow great info! Thanks for sharing!!!

[@willsmith8586]

Ford made a ton of these GT40 parts for ski boats. There are a ton of 351/302 GT40 engines out there. Even ones with Cobra and GT40 intakes. That also solves what the B303 cams are for too. They were designed for boats. Which is why they create power at higher RPMs.

[@KASLCustoms]

Yes I’ve seen them in Nautique boats before as well

[@patrickf4692]

The unique thing about the boat intakes is the lowers for both 302 and 351 gt40 marine engines is they are HEAVY cast iron...

[@EffequalsMA]

I had a set of early 70s 351 heads that I was going to port when a set of TW 170s came my way so, I put down the cutting burrs and sanding rolls. 1969-74 are all good in the 351W heads. 69-74 have the bigger valves, ok compression and no EGR bump. They are no match for a modern aluminum head but, they were the ticket back in the day.

[@KASLCustoms]

Nice find! yes, I agree. Very well said

[@rondyechannel1399]

So Mustang GT 90', Choice '69 351 W 4V, 5.0 E7TE, '97 GT40, '98 GT 40P? Solve the equation.

[@EffequalsMA]

@@rondyechannel1399 69 351W heads are the best of that bunch.

[@eclipsegst9419]

Cleveland heads put em all to shame. Even the 2 barrel versions have bigger ports than the average aftermarket W head.

[@hotrodray6802]

They're just 3 bar heads with big plugs and stud rockers.

[@faststang85]

Some of the gt40s like the ones i have off a lightning have thermactor ports in them as well

[@dragthatsht]

I can tell you for sure ford was notorious for grabbing random parts when they needed them. I got a very early built E4OD in my 94 F350. I know another truck had the "wrong front axle" in a super duty. If they ran out of updated parts they would use what they had until the next batch came in. The guy that built my trans wasn't even surprised. Said he had seen it multiple times. He wrote official ford repair manuals for ford back in the day. Still had copies on his shelf. He came up with some of the updates for their transmissions. It wouldn't surprise me at all if they planned on running the 5.0 for a few more years in the mustang and the accountants told them to switch power plants. Fords accounts have always been what's held that company back.

[@KASLCustoms]

Well said thanks for sharing 👍

[@hotrodray6802]

Like the 428 CJ Fairlane with an 8" rear end. Can't stop the line for a mismatch. Rework would change it later... But didn't.

[@patrickf4692]

I have a set of the original iron F3ZE GT40 heads still new in the box I bought from Ford Motorsport waaaaay back in the day--when they were still selling the Alan Roots heads lol. Fully assembled with the A50 springs, and stainless valves, they sold under part # L303...I also bought a 351 GT40 lower intake with a F2 # that predates the F3 lighting lower....

[@KASLCustoms]

Oh wow buddy! That’s awesome. Hang on to that stuff or at least let me buy them 😉😂👊

[@patrickf4692]

@@KASLCustoms I actually went through my receipts I filed just to see what they used to cost in circa 2005ish. I paid $199.95 for each assembled head!!! When I purchased the heads I also bought the correct 93 Cobra 1.7 rockers for $139.95.....Lol...of coarse still in the box..My greatest trophy is a brand new N.O.S. Bigshot nitrous plate kit 02116 for the Cobra intake. It's the plate that goes between the upper and lower and adjustable from 150-300. Cost was $398.99. Try putting together a HCI with a power adder all brand new--made in the USA parts--for under a grand!!! My 86 GT has true flat top pistons factory, so I put off installing all this stuff until I could do it all...then the Army, then kids blah, blah... you know the story.

[@KASLCustoms]

Oh wow buddy! You are sitting on gold my friend. Good for you!!!

[@Hot_Rod_lincoln]

Just picked up some 69 mustang 351w heads that are very similar to the gt40p heads but without the plug angle and smaller exhaust ports I’ve been doing some research and apparently they were labeled as gt40 style when new.

[@KASLCustoms]

Very cool!

[@jeffhall8282]

the explorers and mountaineers were the last vehicles that had the 5.0 pushrod motor.The mustang and f150 had the modular motor by 96 and 97.The explorer and mountaineer had the 5.0 pushrod motor until 2000.

[@ericmesa949]

Torque monster headers are the absolute best exhaust manifold replacement for any v8 explorer 1996 -2001

[@KASLCustoms]

I've never heard of them before

[@taylormach1699]

Thanks for the info. I think I might put the 3 - bars on my 69 351 mach 1.

[@KASLCustoms]

You bet!

[@midnight347]

I'd get them ported from a good porter before using them on a 351.

[@Mustangdan351]

Some additional info on the GT40 3 bars. The ones that came on the 93-95 Cobra's and Lightning's had the thermactor port's (smog port that the crossover tube attaches to) just like the E7's. I've heard that some of the very early 96 Explorer's also had the thermactor ports, but the later one's did away with them. Also since the Lightning had a 351 it used 1/2" head bolts rather than the 7/16" that the 302's use.

[@KASLCustoms]

Great info! Thx for sharing 🙏

[@Airsally]

Also as seen in your vid the P heads did not have a bolt hole to attach the thermactor a.i.r. tube to the back of the head. I had a set of P heads that only had the aft 2 exhaust ports that were drilled for the thermactor air to blow out of. Good luck with your build.

[@foxfordcatguy2283]

The Explorer/Mountaineer only used the GT40 in '96 & early '97. Mid-'97 & later used the GT40 P which didn't have the thermactor bump.

[@oregonfordguy9812]

we put a 308ci bottom end together, witha. e303 cam, gt40p head, better springs, headers, ssi intake, and areomotive fuel system..

[@damianhughes7034]

Great heads I've managed to get 3 pairs of 3 bar heads and 1 pair of 4 bar had 1 pair of 3 bar ported polished 3 angle valve job lower intake port matched n41 cam should run decent

[@KASLCustoms]

Right on! Thx buddy 👊

[@jgiz6419]

awesome video, i picked up an 89 vert this summer and have been on the search for gt40 heads and intake. The car needs a lot of other work before I start doing performance mods, but if I happen to see an old explorer in the scrap yard I'm definitely going to pick up a set!

[@KASLCustoms]

Thx buddy! Yes these parts are getting hard to find… congrats on the car

[@MP-pz9oe]

Get some Edelbrock E Street, best bang for the buck, exellent quality ! Don't buy chinese junk, is wasted money.

[@randykirchhevel7311]

94-95 Cobra Mustangs have the 3 bar cylinder heads

[@justaguest5332]

There is also a two bar gt40 head they used in industrial and boat engines.

[@KASLCustoms]

oh really? I didn't know that

[@randykirchhevel7311]

I have a nice set of GT 40 3 bar heads which have the Crane 1.7 roller rockers I had a professional Port them with a little polishing which he put them on his flow bench. I will be running a Offenhauser 360 dual plane dual port intake with a step 1 from stock Jegs Roller cam.

[@KASLCustoms]

Very nice 👌

[@randykirchhevel7311]

@@KASLCustoms Thank you building a 1930-31 Model A Coupe traditional late 50s early 60s open wheel hotrod on a 32 Ford chassis with 4 inch dropped straight axle 8 Ford rear out of early 70's Ford Maverick with coil over shocks and 4 link set up in the rear. Its going to have 2" chopped top so which is not very radical but still have that nice look. 94-95 Mustang GT 302 with the Cobra GT 40 heads with AOD transmission. Dry Lake headers. Going with a nice Emerald Green with light metal flake maybe white smoke ghost flames. Its going be like a Bonneville Salt flats racer. I have dreamed this car for a long time just trying to gather all the stuff to build it.

[@KASLCustoms]

That is awesome my friend!! Good for you

[@NoFox_Given]

Wish I could make it to meet you. Just revisited this video to see if there is a possibility to use the GT40 spark plug in a E7. More heat ranges available for a GT40 is the reason. Looks like it’s possible but might be close. The two plugs are 1/4” different in reach.

[@KASLCustoms]

It would be awesome! Sorry I haven’t looked into this yet

[@jacintoespola3781]

La bujia de las gt40 tienen la rosca mas larga y al montarla en la e7 el piston la remacha. porque queda muy adentro en la camara. Y si inst la de e7 en la gt40 la chispa queda muy distante de la camara y trae problemas.

[@sweetassugar2076]

Great video buddy I have a set of 3 bars I found out of a 96 mountaineer. They are getting scarce in the junkyards around here in Massachusetts ! You did a great job explaining the differences between heads 👊🦊🔥

[@KASLCustoms]

Thanks buddy! Good find because you’re right, these things are getting super rare 😬

[@chrisperkins6095]

I got a set of 3 bars with an E-cam. Can I use stock rockers and pushrods? I don’t want to worry about valve cover clearance with rollers. I do have upgraded springs. Thanks

[@KASLCustoms]

You could but I would recommend a good set of roller rockers. I run after market roller rockers with stock valve covers on my coupe. There is a tiny bit of clearancing that needs to be done but very minimal 👍

[@chrisperkins6095]

@@KASLCustoms what brand rockers did you use? Thanks

[@KASLCustoms]

@chrisperkins6095 trickflow roller rockers 1.6

[@matthewmattix]

That is interesting 🤨 I have a set of gt40p head’s that I’ll be using on my 82 ford f150 with the 351w

[@KASLCustoms]

Nice!

[@cecilandrews7479]

For a bone stock engine daily driver the E7 is work fine. But to take that same engine and bolts assetto gt40p heads with intake you'll see a gain of around 30 horsepower. The difference between the GT40 and the gt40p the Gulfport was redesigned which allowed it to use a smaller exhaust valve it has a higher exhaust velocity. As far as changing the plugs I have zero problems with my headers. I don't run 90-degree boots on my plug wires I have a couple of plugs that have 45 degree boots. And if somebody finds that to be a problem, you have more problems than you think. The only thing with the p head that I have found is the headers available. At the time of building my truck there were no long tube headers available. Reconditioned 40 or P heads today or going for 600 to 900. So if someone wants to do some performance upgrades probably better off looking at flotek or AFR heads

[@Anthony-rv3hr]

Did you talk about the springs on the P heads? Supposedly they're only good for .450 lift. I wouldn't toss the P heads on a 5.0 Mustang even with the stock cam without changing those valve springs. Also, you should have talked about the HP you could expect to gain with the GT40 heads over the stock E7s.

[@KASLCustoms]

Thx for this. All of that is coming up in a future video

[@cfrank925]

Thanks for the tips!

[@KASLCustoms]

You bet!

[@randomologist77]

The Explorers were never supposed to get the 5.0. Ford wanted to use the 4.6s from the get-go, but they couldn’t make enough of them. Ford had leftover parts and 5.0 engine production capacity, but the existing 5.0 heads wouldn’t pass stricter OBDII emissions requirements coming in 1996. This forced Ford to redesign the heads for better combustion efficiency, and that led to the GT40P. Ford wanted better performance than the E7s put out for market completion which led to the GT40 heads being the base for the P’s. The reason the spark plug location is different on the P head is because being more centered improved fuel burn.

[@wez50gt]

Nice video mate. Lots of useful info without overload. I’m looking forward to being taken on the journey and learning more. 🙌👍

[@KASLCustoms]

Thx so much buddy! 🍻

[@TheLonni]

Maverick 302 owner... pretty good

[@WhatisReallyGoingOn]

Your video helped me a lot. I just picked up a set of GT40 3 bars with matching intake of a 1990 Indmar marine engine. What is going to be different from regular non marine? Planing on port and polish with a nice stainless valves and titanium seats. Dropping on to a 302 block with some new high compression pistons, for a Fox body mustang.

[@KASLCustoms]

Great find buddy!! I’m not 100% sure if the heads will be any different. I believe the blocks they use on the boats are of a more robust nature however I’m not sure if that carrys over to the heads or not. As for the intake, I believe the only differences you may find will possibly be in the vacuum set up and maybe the throttle body mounting position.

[@chrisgutierrez5759]

The marine GT 40 intake has a cast iron lower instead of aluminum, so it could be used in salt water. There should be no difference in the heads.

[@floydmarseeii4007]

Very cool video and comparison of the 3 different heads. Thanks for sharing. I’m seriously considering porting out a set of E7’s, just because. lol 😂

[@KASLCustoms]

Nice buddy! And that you for the kind words. I’ve heard of guys doing it before I’ve just never heard anyone say that the work was worth all the effort. Let me know how you make out 👍

[@floydmarseeii4007]

@@KASLCustoms Rodney (50Tussin) has a set, that he ran. I think David (The Scientist) did the porting. The E7’s did pretty well. That’s where I got the idea.

[@Airsally]

I home ported a set of E7's pick up 2 tenths and 2 mph in the quarter. So @20 hp. You get more if you do bigger valves like DV did.

[@floydmarseeii4007]

I’m gathering parts for a 387 stroker, this setup drives the compression rate up, so the open chambers of E7’s will help keep it lower to run pump gas. I’m planning to use 1.94, 1.60 valves.

[@Turbo4Joe363]

@@floydmarseeii4007 You're building a 387 stroker and you're going to use OEM cast iron heads!?

[@trailerpark187]

The gt40 and gt40p heads actually burn more efficiently then the other heads. That's what I heard why the Explorers got them. Emissions stuff I guess. I dont know if it's true.

[@huck01955]

Lots of great info thanks

[@KASLCustoms]

No worries!

[@wm9904]

Good shit, just getting into 302s

[@KASLCustoms]

Thank you!

[@wm9904]

@@KASLCustoms building it for a 68 cougar ex drag car. Will get a video or 2 up and def shout you out when we get the far. If you're ever in MN. Give a ring to lake county classics

[@KASLCustoms]

Awesome will do 👍

[@MP-pz9oe]

🤎💩

[@scott3521983]

The GTP40 heads were on the Explorer and mountaineer Because they're the only vehicle sporting the 302 after 95

[@jordanhill8199]

Great content! Excellent video showing the differences/similarities of the three. Do you or anyone else have solid HP/TQ numbers comparing the three? Currently running TrickFlow Trackheat intake and E303 cam with stock E7’s.

[@KASLCustoms]

Thx buddy! I don’t have solid numbers to share but I’ve always gauged the HP gains around 25-30 hp and TQ around 35-50 in stock format ( no porting etc.) That said, every set up is different so it’s hard to say with any certainty but that’s the gauge I’ve always used.

[@jordanhill8199]

@@KASLCustoms appreciate it

[@KASLCustoms]

Anytime!

[@patrickf4692]

It really depends on your supporting mods. My buddy has an '86 Capri and went through a carb phase--he dremeled the flat top pistons to fit stock 3 bar heads and a Weiand Stealth with a 650 carb....even though this was an 86 roller he actually had E5 heads(E7's with bigger chamber) on it at the time trying to get around the piston design and to ditch the terrible E6 heads. He actually picked up an unbelievable 70 HP and 60ish torque!! So basically he went from an '85 long block and added just those 2 mods. This will not be duplicated on an EFI motor JUST by adding either GT40 or GT40P's obviously...with your parts you'll pick up 30-35ish....Of all my buddies that switched to an E cam....they "sounded" faster--but were were typically frustrating to live with and tune --and usually slower than the stock cam. Not a knock against your preference--just something to think about--is the cool idle worth the temperamental quirks for no gain? Only you know that...Regardless with all the supporting mods the typical GT40 top end will make between 255-275 at the tires...Bone stock they dyno 190-200 rwhp. You will feel 75 hp...the cheapest way used to be buying the WHOLE Explorer engine and putting springs and the H.O cam. That's Easy HP and it used to be cheap...

[@KASLCustoms]

Great info buddy!!! Thank you so much for sharing - very valuable for the community 🙏🙏🙏

[@chriswise1232]

I have a set of GT40s with 1.94/1.60 vales, fully ported. My advice would be to use these in their current condition or run something else. They're not worth sending to a machine shop for a performance valve job, guides, and a shave. If i could, i would lend my younger self $300 and say, "Get some trickflow heads and be done."

[@midnight347]

Big dog does killer porting. He can make these outflow most aftermarket aluminum heads.

[@chriswise1232]

@@midnight347 Most aftermarket heads will flow 240-320cfm on the intake side. With big valves, the GT40 heads will top out around 245cfm. He actually did a video on this.

[@hotrodray6802]

🔔😎🇺🇸 3 bar heads are basicly and simply '69-70 351W heads with small spark plugs and bolt down rocker arms. I used to port heads. 😎

[@patg9283]

Great video. Any chance your going to the international Mustang meet in Saskatoon?

[@KASLCustoms]

Thx buddy! No I won’t be making that one unfortunately… 😢

[@jackcarriger7200]

I always just figured they figured the suv may need the gt stuff for towing and also the suv weight more?

[@KASLCustoms]

I know right 🤷‍♂️

[@sorshiaemms5959]

gt 40 3 bar are very close to a 1969 to 74 351 Windsor head same valve size with a little better exhaust port

[@KASLCustoms]

I did not know that. Thanks for sharing 👍

[@Hot_Rod_lincoln]

Just picked up a pair of these heads “c90e”. Very similar to the gt40p but yes exhaust ports are smaller and closer to e7

[@hectorortega9131]

Hello I'm new to your channel and actually this is the first video that I watch, So what head is good for what intention on what motors and so forth? Tnks in advance.

[@KASLCustoms]

Hi there, are you trying to decided between GT40 & GT40p?

[@russriley3005]

on these heads you never mentioned the potential of them after porting. i used to take a set of old 70s 2 bbl chevy heads and make them run like a double hump heads. can you do that with e7 heads?

[@KASLCustoms]

Not that I’m aware of

[@eclipsegst9419]

you can make a fair bit of improvement, i'm not sure how much thickness there is to work with exactly though. Certainly enough to match any other factory head. IDK i dont mess with those tiny port Windsor heads anymore, Cleveland heads are the way to go.

[@russriley3005]

@@eclipsegst9419 if you are going for power, it might be more cost effective to get aftermarket heads. I want my engine to look stock. that is why I want to use the e7 heads if I can

[@eclipsegst9419]

@@russriley3005 ported e7s will do for a 302. I generally mess with 351s, those 302 blocks are iffy above 450hp. For a 351, you can't go wrong with a C head, be it a reproduction iron 4V or something aluminum.

[@G.Harley.Davidson]

I screwed up and tried to clean my GT-40p valves ( exhaust and intake ) in a hot tank and etched them up bad. I have a set of Mustang GT, E7, valves, so can I use those in a GT-40p head? Thanks

[@KASLCustoms]

Thats odd, what was in the hot tank...?

[@G.Harley.Davidson]

@@KASLCustoms muriatic acid diluted. The GT-40 heads use a 1.84”/ 47.8mm intake valve, and the E7s use a 1.78”/45mm intake valve, so I guess I’ll have to buy new valves dammit.

[@m.pietro9087]

Thanks for clarifying. Can I use the GT40 heads on my 1988 Lincoln Town Car with the stock intake manifold? Thank you.

[@KASLCustoms]

I believe so but the intake is one of the big choke off points on the 5.0’s

[@m.pietro9087]

@@KASLCustoms thank you. I think an aftermarket intake manifold is the way to go.

[@KASLCustoms]

Yessir!

[@marianomruiz]

Hey why do the front coolant passages are covered when installing the head gasket and the rear open. Why ford went through the trouble of doind passages on the front and then they are covered by yhe gasket gt40p.

[@fordguy8613]

Combustion chambers size on the explorer gt40's were bigger than the cobras.

[@kevingilroy]

Thanks for the close up on the P head. After watching another guy ramble on about stuff he read on wikipedia. You clearly show the real problem with the P head. The spark plug is too close to the intake valve. It really needs to point to the exhaust valve. Why? Because in boosted or nitrous cars. It can actually ignite the fuel mixture back into the intake. And we have all probably seen those explosions at drag strips. Also, I may have missed it, Where do we find 3 bar gt40 heads? Or on what?

[@KASLCustoms]

You’re welcome. The 3 bars came on all 93 cobras

[@kevingilroy]

@@KASLCustoms probably not so easy to find. But thanks.

[@KASLCustoms]

No worries 👍

[@quinton3997]

I've got a set of 87 thunderbird heads that have a smaller combustion chamber I'm not hearing anyone talking about those

[@MrMackch613]

Where does everyone find the info to be able to match cam with heads with intake etc. or more importantly how to tell what you have when you buy a used car. Thanks for this video i need to know what i have for heads

[@KASLCustoms]

You’re welcome. It’s best to speak with someone that knows what they are talking about- like a reputable machine shop or engine builder. It can be a very confusing path to navigate if you’re unfamiliar

[@billsmith360]

Your question has no answer because because you give no info. What car? What engine? What year? And what do you want to do? I can help but you need to first fill the questions asked

[@randybelcher6693]

I could be totally wrong but I thought the GT40 3 bar had 62cc chambers and the 4 bars had like a 58cc

[@THE-SHOP]

I believe so.

[@patrickf4692]

I have a pair of brand new in the box L303 heads which were sold through Ford Motorsport way back....Just as a reference point they are assembled F3ZE heads and specs on box says 65.5 cc chamber.....I measured them anyway and I got 63 cc. I've seen them anywhere from 62--68 cc depending on what they came off...

[@THE-SHOP]

@@patrickf4692 sounds about right for 3 bar heads. 👍🏼 4 bar P heads are 58-59 ish CC’s

[@WARD5KUSTOMZ]

Trying to figure out which one would be best on my 351W HO block

[@brianlucero9536]

Soooooo help me out please. Im running on an Old 1989 v8 302 automatic bronco engine, planning to overhaul it and add gtp40 heads and a e303 cam. What else should I do to make it better more efficient? Maybe a better water pump? Idk really

[@KASLCustoms]

by "efficient" Do you mean you want to make it better on fuel?

[@brianlucero9536]

@@KASLCustoms well yeah, kinda. Stronger, faster, better fuel economy would love to use it at comfortable 80-85mph. My go to option rn is getting a junkyard 5.0 HO explorer engine and cam it

[@KASLCustoms]

@brianlucero9536 lol - you’re asking a lot there… driven nicely, my HCI set up can achieve high 20’s/low 30 mpg on the highway

[@jeremyplester3915]

I wish you had a header or manifold to show the difficulty with p heads, but it was a great video as I would love to put a gt40 set up on mine one day. I am also curious as to why the explorers got the gt40 set up.

[@KASLCustoms]

Sorry buddy. I didn’t have one laying around at the time 😢

[@jeremyplester3915]

@@KASLCustoms still a great video. Thanks

[@KASLCustoms]

@@jeremyplester3915 Thank you!

[@patrickf4692]

I thought I remember reading it had to do with emissions changing...even though they were phasing the old pushrod tech out...the explorer still sold like crazy, and I believe the thinking was to put a tiny little cam with better head and intake flow, so to not have to run all the smog gear of previous 302 models...they apparently couldn't cut if they had to redesign the heads to even cleaner burning P heads... If you've ever seen a header from a 302 explorer, you'd be amazed it made what it did...

[@KASLCustoms]

Yes I think you’re right on that. And those headers are pitiful…

[@PrittFamily]

So, when are you planning on the next video to discuss specifics of your retro GT40 build? I'm sure I'm one of MANY that is highly interested....because it's exactly what we want to do! In fact, it's what I'm gonna do! I already have the heads, upper and lower intake off a '97 Explorer sitting in the garage....ready to go! So, let your fanbase know!

[@KASLCustoms]

Hahaha thx buddy! I know I am excited too but I don’t want to start tearing the car apart until we he end of the driving season. I will however start tearing the heads and intake apart shortly to clean them up etc. thx for reaching out 👍

[@PrittFamily]

@@KASLCustoms Driving season? Being in Tampa, Florida I'm not familiar with that concept! Actually, Jan & Feb are arguably the better months for top-down around here. I went for a drive yesterday and sweated unreal! I'm thinking western Canada would have been a nicer drive yesterday! Thanks for mentioning your podcast...I didn't know! I'll be checking that out too....without my daughter around apparently!

[@KASLCustoms]

Hahaha yeah I wouldn’t even imagine being able to drive in Jan/Feb around here ⛄️😂. We have a lot of fun on the pod. I find that putting a podcast on while cutting the grass or something to that effect is nice because it allows your mind to be somewhere else while doing mundane things 👍. Also, we do get quite passionate and “colourful” with some of our language so maybe pick and choose the parts you show the younger ears…😉🍻

[@oscarvillarreal8951]

If everything was stock in a foxbody and all I did was change the heads to E7's to Gt40's? Would you have to tune it?

[@KASLCustoms]

No sir, I would say you’d be totally fine

[@oscarvillarreal8951]

@@KASLCustoms what about just aluminun heads?

[@KASLCustoms]

Same deal 👍

[@oscarvillarreal8951]

@@KASLCustoms thanks buddy 👍

[@KASLCustoms]

Anytime 👊

[@shafferjoe1962]

Thank you sir.

[@KASLCustoms]

Youre welcome

[@ML-dl1cp]

Hey just stumbled upon your channel... Are you on the Island, by chance?

[@KASLCustoms]

Nice! No sorry I’m not, I’m in the Okanagan

[@leftcoastdrifter]

great info!

[@KASLCustoms]

Thank you!

[@longshot82383]

Picked up a 1969 351W for $50 should I just junk the E7 heads it came with?

[@KASLCustoms]

Nice! I would try and sell them first

[@rexmasters1541]

Its easier and better to buy after market heads than what your doing.

[@KASLCustoms]

Been there many times as well

[@adamrushka8096]

Did you decide on a cam yet ?

[@KASLCustoms]

Not yet… soon 👍

[@chrisj2713]

Thank you

[@joeyleinart8354]

Probably because the tooling was setup and ready to be used in something

[@trading7708]

Hi! Bro, What's the correct sparks plugs for gt40p?

[@KASLCustoms]

I’m not sure off the top of my head. Have you tried google?

[@trading7708]

@@KASLCustoms yes, awsf-32EE ,but i don't find a equivalent. Thanks anyway!

[@KASLCustoms]

@@trading7708 here is a link that will help you: www.sparkplug-crossreference.com/convert/MTRCRFT_PN/AWSF32EE

[@barrykennedy9947]

The spark plug location isn't a big a hurdle as people make it out to be.

[@chozen_pacolmx6436]

Hey KSL I have a 95 5.0 SN95 My crankshaft broke bcuz it was the same crank from 95… So I told him to redo the whole motor so he’s puttin gt40 s and p heads and headers with 373 rear end gears, new rods and pistons with throttle body everything will be performance do u have any advice on what else I should do I want it to be a street car that I can take in the track from time to time

[@chozen_pacolmx6436]

Or do u think I’m at a good start?

[@KASLCustoms]

Hey bud - I think that's a great start. It will feel like a whole new car when you get it back 👍

[@chozen_pacolmx6436]

@@KASLCustoms thankx for ur Honest My ankle said the said thing it will feel like a new car with more hp

[@KASLCustoms]

💯

[@cnebuda7422]

didnt they use p heads for the "efficient" design of the chamber? better fuel economy/burn etc

[@KASLCustoms]

I think you’re correct on that 👍

[@jdwht2455]

Good comparison. I have 302/5.0 in my '31 roadster. It has the 4 bar GT40P heads that came on the Ford Motorsport crate motor. Sanderson FF1 headers will work with those spark plugs in a street rod tho a couple are socket close but headers don't need loosening. 90 degree plug wire ends are a necessity as you noted. You do need to be aware that the Fel-Pro and other catalog listed OE type intake gaskets are a poor choice and partially block the ports. I did a search and found some that are perfect but unfortunately during a house move my current build sheet disappeared so don't have the Fel-Pro part number. The one thing I should have done was to open up the exhaust valeve to the 1.54 version but since the car is now for sale, someone else's project

[@KASLCustoms]

Thx sir. Thx for sharing as well

[@MichaelRoe-y5u]

I have an early fox 302. Do GT40 heads benefit flat tappet lifter 302s

[@KASLCustoms]

I'm guessing you mean solid lifters? if that is your question, that is more of a cam consideration

[@llb8851]

If the 40p heads gt40 cast intake are so great. Why does my 98 explorer only make 215hp. Cam ? Intake ?

[@midnight347]

It has a super mild truck cam and restrictive exhaust manifolds...

[@cesarreyna6517]

What kind of compression i can get on a 302 with gt40 and flat pistons?