Cure Heat Soak - Intake Block Off Plate

[@vetteseller5]

my 71 vette after rebuild, had vapor lock 7 times. left me on the side of the road 7 times. I did everything else but this. doing it now and hope I can drive my baby without worrying about that darn vapor lock. thanks a bunch. - Pappy

[@67Redlines]

Your explanation and clever way of blocking the exhaust from going into the Intake Manifold is genius. Good explanation and video. These are the kind of videos that help an individual step through and understand a subject matter. Great Video.

[@stevebrown8299]

I like this channel, working on an old 350 truck. Had to go thur everything, rolling restoration over years. Problems everywhere, watching your videos has really helped. Thank you

[@MuscleCarSolutions]

Glad to hear it! Thank you!

[@mikef-gi2dg]

I did the exact thing many many years ago, I lost the set that came with the gaskets, and I made some up. I worked great. I have been restricting the cross over more and more over the years, especially with stock intakes, with no issues at all. These engines don't get run with freezing temps out side anyway. I have recently modified several aluminum and iron factory intakes to resemble performer type intakes, and have eliminated the cross over entirely. For my mild performance SBC engines, I think it will work out fine. I going for the stock looking performance sleeper look. Time will tell.

[@zumintroy]

The heat crossover is used to heat the floor of the intake manifold so that any liquid fuel that has separated from the mixture will be vaporized. This becomes more of a problem as the air temperature gets colder than 50 deg F.

[@Driven_Dragon]

I love Gasgacinch! I use it on both sides of any fuel related gasket. Never have ANY vacuum leaks EVER. Best insurance and makes the gaskets reusable as well.

[@MuscleCarSolutions]

It’s a great product no doubt.

[@jameshoneyc]

Some guys are welding theirs closed. I think I'll do this less permanent and a lot easier. Thanks for the video.

[@sbcbuilds5517]

Requires zero machining too. Welding them shut is just an entire different ball game. Not even worth it for an everyday build lol

[@Mattys91gt]

What did u use to block off the hole mines on a foxbody mustang

[@oantech4252]

I only use Felpro blue gaskets. I throw out the front and rear rubber rail gaskets and run a 1/4" bead of "The Right Stuff" form a gasket on each rail. Let it sit for 15 minutes and drop the intake in place and tighten it up. A perfect seal and no oil seepage. I also find it necessary to re-torque the intake after initial run-in only with aluminum intakes for whatever reason. I have had water leak into the combustion chamber and show up at the tail pipe before re-torque. This is from years of Chevrolet experience. I hope it helps someone.

[@MuscleCarSolutions]

For sure an old trick that takes care of those pesky front and rear seals. Thought of doing that video but there seems like there is a hundred of them on KZbin. 😆 Hope everyone knows that one by now! It saves a ton of frustration and mess to clean up!

[@ohm1945]

Retorque the intake manifold bolts. Never read that in any workshop manual but it makes sense with an expanding contracting aluminium. Point noted and thanks.

[@urcarsucks6959]

I have a weiand tunnel ram with Brodix heads on one of my small blocks. For whatever reason, the space between the intake and block at the front and rear was seemingly larger than usual...would have taken a very tall bead of RTV. I've had trouble with RTV beads sealing in the past, and given how much RTV it would take, I opted for a new method. A fairly tall bead of RTV paired with cork gaskets. Works very well, no leaks whatsoever

[@jacobsabian4386]

i used an old license plate cut the exact same way and used rtv to keep it stuck to the gasket on installation 👍

[@masonite1973]

Nice, I had the same thought on this Oldsmobile 350 I am working on. Glad to hear it worked for you

[@jessemendoza2991]

@jacobsabian4386 With the license plate, did you flattened it? Thanks

[@mason5540]

@@jessemendoza2991 I ended up using a 4 in. x 16 in., Stainless Steel, Door Push Plate from Home Depot. It is 1/32 " thick. Cut 2 pieces to cover the exhaust ports, and cut out matching sections in the gasket so there wasn't any overlap. The thickness is a good match with the gasket, ever so slightly thicker. Working well so far. Wanted something a little stronger than aluminum license plate

[@seanjohnson6899]

Used stainless steel shim cut to fit and copper rtv to close off the heat cross over from the stock heads to my new edelbrock performer intake manifold on my 390fe. Not sure how much it helps with horsepower but living in Southern California it can't hurt.

[@xexdsr]

I've cut up a beer can once and it worked pretty good

[@MuscleCarSolutions]

Too thin for any long term use for me. I’ve seen single layer cans burn through. If I were to use I’d at least double em up. Maybe more.

[@hotrodray6802]

It's also for prevention of carburetor venturi ice. Remember the exhaust manifold flapper valve? But heating the carb also happens in the summer Remember the exhaust manifold heated snorkels on the air filters? That helped too.

[@MuscleCarSolutions]

That was very relevant back when there was lead in the fuel. With todays ethanol added fuel? Not so much.

[@larryburns4605]

If not in cold climate use felpro 1204

[@robertclymer6948]

Good Stuff! Was not aware of this Mod, but I am now. Thanks for sharing! Blessings from Motown.

[@MuscleCarSolutions]

Anything to keep the heat out of the manifold! And making them is just a result of trying to get a manifold on and not having the block off plates! Gotta get creative sometimes! Thanks for stopping by again Robert!

[@robertclymer6948]

@@MuscleCarSolutions I really appreciate a man that can think on his feet. I fab tools, rather then spend tons on something I might use once or twice. If I owned a welder, I would be a mad scientist in the garage. lol

[@MuscleCarSolutions]

@@robertclymer6948 I grew up poor. You had to get creative if you wanted something. lol Hard work creates opportunity!

[@robertclymer6948]

hello again! Could you please tell me how thick the piece of aluminum was from the Jasco Acetone can? I see you check with your micrometers but you didn't say. Would really appreciate the thickness please. Really appreciate it. I am ready to install my permormer rpm on my 460 big block in the next day or so. Cheers from Motown.

[@briang4470]

You should add a little disclaimer that if your running a hot air or divorced style carb choke, that you cannot eliminate the crossover or the choke will never work properly. But I understand that 95% of people with these old school engines are either using an electric choke,manual choke or no choke at all so for those folks it doesnt matter but there are still guys, my self included that still have a divorced choke system which I think works well and in the mid to late 70s there were alot of "hot air" style chokes where a steel tube was placed in the cross over amd air would be pulled through that heated tube and warm the choke spring so for those applications a heat cross over is necessary.

[@MuscleCarSolutions]

It’s a valid point, however there are only just a very small numbers of aftermarket intakes out that have a provision for the divorced choke. This performer EPS does not. I don’t disagree that the divorced style choke works extremely well. On a stock intake there are endless numbers of those in the 60s and 70s that used that style and for sure you can’t block off its source for heat. Had I done gaskets on the stock intake that would have been a highlight of the discussion as this truck had the divorced choke Qjet.

[@briang4470]

@@MuscleCarSolutions I have an old edelbrock performer aluminum qjet style dual plane on my c10 and it has the pedestal for the divorced choke spring to mount to. I have an early 1968 qjet with the divorced choke and I bought edelbrock part number 1931 which comes with the choke spring and rod and got the whole choke system to work just like stock and it works great, it was one of the best things I ever did because when I first got the engine it had the choke wired open and the idle circuits on the qjets are so lean that it didn't want to idle until the intake got a little heat in it and after making the choke work properly it works almost as good as fuel injection. Just 1 pump in normal weather 2 pumps in very cold weather and starts right up and warms up quickly.

[@MuscleCarSolutions]

@@briang4470 yup, most likely it’s the old 2101. Great intake. The EPS is the upgrade to that intake. The 2101 had the mount for the divorced choke but the newer version doesn’t. I love the simple solution they created for the choke back then. Kind of hard to argue with how well they work!

[@onsturn]

Would blocking off the crossover for the old school divorced choke intakes running above 50-degrees really be a concern?

[@IronHorseGarage]

This is some great information!!! Keep it coming!!!

[@MuscleCarSolutions]

Very much appreciate that. Thank you! I’ve got quite a few ideas of stuff to share. Just hope to have time to get it all done!

[@jamesharrison6201]

Heat crossover has nothing to do with leaded vs unleaded but as you said it's there to help vaporize the incoming fuel for better distribution to all cylinders. Of course the alcohol will vaporize faster than the gas but not enough to affect performance. When you begin to block off the crossover is in racing applications

[@MuscleCarSolutions]

Leaded fuels didn’t have the heat soak issues that ethanol added fuels do. No, not just “racing applications” need to heat cross over blocked. Heat soak is an issue even in the mildest street applications. All goes back to that awful ethanol fuel. Performance isn’t the factor. It’s the boiling of the fuel in the carburetor after the engine is brought to operating temperature then shut off.

[@dewholdingsllc1050]

Good tips. I like the recycled can.

[@triumph928]

Always used old license plates to make block off plates. Never had one leak or burn out.

[@MuscleCarSolutions]

Well that would certainly be thick enough!

[@maxxmasson4263]

Great tip

[@josephgenovese1146]

Great video those exhaust crossover is about 20 horsepower loss

[@MuscleCarSolutions]

It would be an interesting dyno test to see if any or how much is lost.

[@therealhip9321]

I make like a big T. The bottom of the top bar rests against the 2 bolts so it doesn't slip down.

[@stephenvanvliet9812]

I’ve seen a few of your videos. Always great job explaining what’s going on. This video speaks to the exact question I have right now. I have a pretty stock 350 sbc, maybe a mild cam in there (not sure exactly) with original heads that have the crossover port. I bought the airgap intake manifold and the AVS2 carburetor. The intake as you probably know does not have the port. I’ve gotten a few answers here. Edelbrock told me I can use their gasket and simply cut out the perforated box and just let the crossover port blow straight into the aluminum blocked off material on the intake. I currently have the felpro 1204 gasket that has the metal blocking. Which I believe is what you refer to in this video. Can you simply provide your opinion towards my plan that I would be good with original head with open crossover to 1204 feltpro with blocked off metal square, sandwiched under the airgap with no port?

[@71lemans]

Stainless steel kick plate off a door works great

[@MarcBchannel]

Ive heard that the power loss of running the crossover with a tight lsa cam is considerable compared to a wide lsa or stock type cam.

[@paulrivas5214]

I just used a two block off plates and the dry fitted the intake and it’s not sitting flush. Is that gonna be an issue or would it sit flush once I tighten it down?

[@larryboyer]

To be clear you have the block off on the side that will be against the head, and the side with the striping to the intake manifold, correct??

[@stuckinmygarage6220]

Good point: aluminum intake and today's fuels. Thank you

[@MuscleCarSolutions]

Gotta keep fighting that ethanol! Thanks man!

[@StevenDale-y6v]

Always block it off, now days. Also old cast iron intakes crack underneath the carb and will cause vacuum leak in the crossover area.

[@Ecosse57]

​ @Muscle Car Solutions nice and straight forward. i've got a car never driven in the cold months and with a cast iron intake; should i bother with a block-off?

[@MuscleCarSolutions]

I’m not sure I’d crack into an engine just to put the block off plates in, but it could help with getting a cooler fuel and air charge. Don’t know how much of a difference it would make.

[@Ecosse57]

@@MuscleCarSolutions basically stock ford 302 right now with factory 289 4 bbl intake. wonder if a insulating plate between carb and carb base would help. i'm not having any heat issues but anything cheap to help is worth looking in too. thanks man for chiming in. great channel!

[@MuscleCarSolutions]

@@Ecosse57 absolutely! I’ve done a video on how to cure heat soak addressing things to do with the carburetor. Isolating the heat from the carb is an excellent idea. Ethanol boils at 180 degrees. Anything to help that survive will keep things running smooth. Thanks for watching! Very much appreciate it!

[@seanbrooks9308]

@@Ecosse57 Might wanna consider a 1/2 inch or better phenolic spacer from Ebay.. then look there for Fuel Insulation line covers... Easier than being stuck in traffic with car dying in summer, or go in store for 15 minutes, come out and car not start...

[@stuckinmygarage6220]

@@Ecosse57 Do it. Your car(b) will love you. Watch for hood clearance.

[@hybridmusclegarage4590]

Great info. I always block mine off

[@MuscleCarSolutions]

Always so when I go to an aluminum intake. Sometimes don’t if doing a stock engine.

[@eddierios5371]

Do you block one side only or the restricter have to have a small hole

[@hybridmusclegarage4590]

@@eddierios5371 with or without small hole is ok. I do completely blocked(no hole)

[@3DInterceptor]

So what thickness was the can you cut up ??

[@vientosnomadas655]

so is this the reason why my 5.7 TBI bucks at 5% throttle when warm? like when you're juuuuuuust touching the pedal in a parking lot or something.

[@JARRETT7121]

A lot of heat soak is determined by how much muffler exhaust restriction there is Free flowing aftermarket exhaust versus Factory choke off exhaust

[@MuscleCarSolutions]

Kind of. But even with a free flowing exhaust and the cross over blocked, heat soak is still a very real issue. Thankfully there are some good solutions.

[@gb123-ej8wh]

Uncle Tony welds the exhaust pass through port closed on the heads.

[@MuscleCarSolutions]

@@gb123-ej8wh your uncle Tony has more ambition than I do!

[@stevekline1171]

good job , but will this work with a big block olds motor with the aluminum valley pan .

[@MuscleCarSolutions]

Don’t have a clue! Anything with a valley pan is a bit of a challenge.

[@rivernorcal679]

Yeah buddy! Thanks!

[@redlineexteriorwashing8764]

Interesting, I actually purchased "1205" gaskets for this problem, but I realized I wasted my money. The 1205 are for performance intakes the don't have a crossover. There is no reinforced metal inside the 1205 Gasket that sheilds crossover, Its just a gasket that doesn't have a crossover because it is meant to be installed against solid metal of a high performance intake, I think this is important for newbs like myself. If I'm wrong please someone correct me. I am setting aside my 1205s and staring at an almost empty can of Denatured Alcohol and standard Blue Felpros I have from the rebuild kit.

[@davidrowland2354]

1204

[@beking32]

I left mine off my stock 4.9 Cadillac engine. Will this cause issues?

[@deerslayer5863]

I used pop can block offs after a while they burn throw

[@MuscleCarSolutions]

Yup. The aluminum is just too thin. Made that mistake before too! Always learn something.

[@deerslayer5863]

@@MuscleCarSolutionsnow i just go buy those alumiun braseing rods fill up the ports grind it flat and call it a day works great

[@MuscleCarSolutions]

Whatever is cheap and easy!

[@victorrobinette114]

I have some galvanized steel that gauge.017 thou. Is that to thick. What gauge do you recommend besides a Acetone can. Thanks

[@jackjenkins4784]

Hi, I have a 1984 C10 305 V8 Original, Cast Iron Intake, Electric choke, small metal line comes off the exhaust below the exhaust manifold for helping warm up engine( when cold closes when hot opens) works off vacuum on exhaust on passenger side. Has EGR Valve on cast Iron intake, but I have Removed smog control. Will it be safe or important to close off the heat cross over on this cast iron intake before reinstalling? Thanks for info

[@canyondanhandyman1784]

You mentioned Fel pro 1204 kits which look like they have the crossover blocking plates included. Have you used the 1204 gasket kits? Do you like em? I could still order those for my 69 C-20 with 400 SB Thanks!

[@MuscleCarSolutions]

They’re good. Though I end up using the Edelbrock intake gaskets on every intake I do now. They match the ports perfectly. I looked at a C20 this week. Was just a little too far gone for me.

[@RealWorldGarage]

Well laid out video and voice over.

[@MuscleCarSolutions]

Very much appreciate that! Thank you!!

[@Dookieandsons]

I need to do that today I have a 84 or 85 Camaro 305 ho factory GM intake I'm putting on my V8 Blazer it's got Street fire MSD distributor Patriot headers 650 Edelbrock avs2 but I had my stock TBI intake manifold with an adapter so basically it was like a two barrel intake I think I blew my intake gaskets Monday so while I'm at it I'm going ahead and putting that four barrel intake but I was noticing the intake runners being blocked off on the back of the TBI intake but the back of this 305 ho intake doesn't have the flow in the back of it but I was noticing the exhaust crossover I want to block that off what metal did you use or how thick I probably got something else I can use so how thick

[@rick86chevy16]

My intake do not have the EGR ports on it and it's a Edelbrock air gap intake so I was wondering can I still run it on my small block Chevy

[@MuscleCarSolutions]

@@rick86chevy16 two separate things. The exhaust cross over is not the same as the EGR valve.

[@jamessiro5409]

Do you put the plate in the head side of the gasket

[@johnweaver8470]

Could you do a video on carburetor icing, it's a real headache on my old 4x4 Chevy 454 and edelbrock carb ,is it because I'm using a open air cleaner with out a heat duct from the exhaust to the factory air cleaner? Thanks for the videos and advice

[@MuscleCarSolutions]

I’ve really only experienced this on motorcycles. How frequently is this happening for you?

[@johnweaver8470]

@@MuscleCarSolutions in the winter when it's in the 20,s and snowing when I need it the most can actually see frost on front of the carb I have to let it run for awhile shut it off for 5 minutes then it's good to go for the rest of the day, live in Washington state lots of humidity if that makes a difference seems like it's not a problem when it gets down in the 20,s cold and dry air thanks again for responding, I'm usually asking you something about my 68 396 Camaro

[@zumintroy]

Yes

[@shoe2241]

thank you sir, very nice video !!!

[@lildeena1]

Awesome!

[@MuscleCarSolutions]

Thank you

[@oldmanintheshopbuiltnotbou8726]

Good tip just subbed

[@MuscleCarSolutions]

Cool! Glad to have you here!

[@jamesharrison6201]

In addition, my 77 Ltd 11 was upgraded to a Torker 2 manifold and never had a problem,, worry about crossover on a aluminum manifold. Will say fuel mileage went from 15mpg at 60 to 18-19 at 80. You youngsters, to me, worry way to much about nothing.

[@MuscleCarSolutions]

The torker intakes didn’t have a heat cross over, so nothing to block to stop the excess heat into the manifold. Your mpg claims are not possible. Not with that god awful torker intake.

[@mikesautomaintenance5780]

So I just pulled my old man's intake off to replace the gaskets why would the back water ports be blocked off ? 93 350 tbi

[@MP-io7yj]

The intake probably doesn't have water ports in lot of them were sealed off

[@mikesautomaintenance5780]

@@MP-io7yj it has water ports on the intake I guess I should of said why is the gaskets back water ports blocked off they had the little metal block off plate like he shows on here with the little pinhole through it on the gasket itself not the intake

[@tylerdavidson4645]

hey man fyi your using left handed snips and i noticed you seem to be right handed snips are color coded red - right handed green- left handed yellow - straight

[@tylerdavidson4645]

not saying your doing it wrong just some useless info lol

[@MuscleCarSolutions]

Nope. You’re 100% correct. I have all three. The green ones were my Dads and I still instinctively reach for them. More precise work I’ll dig out the counterclockwise or straights.

[@armandomendoza3167]

Does this help with vapor lock issues?

[@MuscleCarSolutions]

It helps isolate the heat from the manifold, yes. Which will help with heat soak issues in the carburetor.

[@armandomendoza3167]

@@MuscleCarSolutions Thank you for sharing your valuable knowledge and wisdom.

[@MuscleCarSolutions]

Anytime! Glad to be helpful to you!

[@maxxmasson4263]

It should help since the plenum under the carburetor will be cooler

[@steveproctor1748]

Just cut a piece out of the old gasket. It will make your exhaust smell kind of rich.

[@Aceman597]

Im thinking top or bottom of tuna , soup , chili can.

[@MuscleCarSolutions]

Probably work just fine.

[@jimstewart8394]

i have found that annular boosters don't work without heat crossover, just my one time experience.

[@MuscleCarSolutions]

How do you come to that conclusion?

[@jimstewart8394]

@@MuscleCarSolutions i welded the holes up in my edelbrock intake and changed to annular booster then would not run worth a crap, changed back to down leg and runs fine that's with 2300 holley using the same carb

[@MuscleCarSolutions]

Your problem isn’t with the cross over. There’s another issue here. Going from a 4 barrel down to a 2 barrel didn’t correct it. It’s covering up what the actual issue is. So many questions.

[@diesel1586]

Nice

[@seanbrooks9308]

Hell... my '72 Monte Carlo stock with Rochester 2BBL needs this done. Instead putting phenolic spacer on carb, fuel pump, and some insulation I got on Ebay for exposed fuel lines... and on top of that, got myself a marine inline bildge pump blower to mount on frame to blow on fuel pump to help keep cooler... running 3 inch line to front of car to pull air from. Yep, maybe overkill, but you sit on side of road waiting for everything to cool down in Texas Summer heat so car can be started in rush hour traffic!!!..... Go Biden/Harris... make america suffer.

[@MuscleCarSolutions]

Oh I understand. The heat in the mid south isn’t much better. Anything to keep these things cool!

[@davidrowland2354]

Felpro 1204

[@PrTOSHIBA]

I used a soda can before. It didn't last haha

[@MuscleCarSolutions]

Yeah that thin aluminum doesn’t stick around very long!

[@44hawk28]

Leaded gas has nothing whatsoever to do with it. If you're running a carburetor in the carburetor has to run on the street, you better have it or you're going to be spending a lot of time fixing problems due to fuel that doesn't a demise well especially the summer blend that they insist on people running anymore. Summer-blend, by Design, does not vaporize as easily as winter-blend fuel. And yet, they charge you more for the summer blend fuel that you will get a little bit less fuel mileage with. I don't mind the idea of restricting how much heat goes through that passage, but blocking it off is a recipe for racing, not for driving it and day-to-day activities. Because you have to keep the carburetor warm especially in any kind of low temperatures. And if you are looking for fuel mileage, you do have to keep that fuel warm as it tries to cool the intake air charge as its vaporizing. Remember that gasoline, in and of itself, does not burn. Only the vapors burn.

[@MuscleCarSolutions]

I’m afraid leaded/ethanol fuels has everything to do with it. In the 60s when lead was present in the fuel, it had a higher boiling point and wanted more of that engine heat to start the process for a more effective burn. Ethanol contaminated (and it is an awful contamination) fuel has a much lower boiling point and doesn’t require that same amount of heat. If all things from the 60s till now remained the same, then yes we wouldn’t be having these issues with todays fuel. Eliminating as much of the heat source as possible is what allows todays engines with a carburetor to operate easier. We fight this daily with folks asking how to keep their carburetors from boiling over. Blocking the crossover is an excellent way to help block some heat.

[@RickyJimenez-tn8gy]

What was the thickness of the material you used?

[@MuscleCarSolutions]

One acetone can thick!

[@jonjon5302]

@@MuscleCarSolutions thank for the video, You measured it with a micrometer... so what was the thickness?