Hey im creating this thread because the old pontiac swap thread is fading. In this thread im going to chronicle the rebuild of my 1974 pontiac 455 and the actual swap into an early 80's t/a or iroc. I have not decided what car to choose but i will keep everyone posted when I do decide which one. I will also talk about transmissions to use. As of now i have a th400 and thats what i plan on using. I WILL SHOW PLENTY OF PICS!!! I will also show the mods needed such as what tyes of headers and manifolds will fit, the types of engine mounts and the types of transmission mounts needed for this type of project. if i have missed anything im sure you guys will cover it.

 

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So far this is the Pontiac 455. I am keeping it a mild rebuild. I also have just ordered the rebuild kit. ill show more pics when i start putting it to gether.

 

This is the exaust system i found and that i will have custom made but its up to you what you want.
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Looks good. I would love to see this swap, as I know the Late 60's 455 engine produced gobbs of torque. Should be fun. Now lets see you pick up a firebird to drop it in!

 

you betcha thats what im prob. gonna buy instead of an iroc cause it would be a little easier.

 

I'd buy an IROC and put it in there. Pontiac owners have been getting screwed with Chebbies V8s under the hood since 1982. Its time to return the favor for GM's wrong doing.

I recently picked up an '82 T/A with a junk drivetrain that will probably end up being Pontiac powered someday. I'd like to try to build it the way is should have been and get a Turbo 301 in there.

 

idk i will def. inspect the car. but im not going to be suprised if somthing brakes, because of how old they are.

 

what kind of intake/carb should i go with for a 455?

 

Its hard to beat a stock intake and quadrajet. Pontiac was good about designing things about as good as it gets. '73-79 intakes have EGR provisions so they are a little heavier. Might look for a factory aluminum '69-72 RA IV/HO intake(big bux) or Edelbrock Performer if you want to reduce some weight.

 

How much cfm would i need?

 

nice, i may do one as well, i have a 400/400 combo that is sittin , waitin, needin a home. ill keep an eye on this thread. as for carb size, at least 750 cfm

 

Pontiac typically ran 750 and 800 CFM QuadraJets.

 

ok thanks! this saturday im postin up more pics of the engines progress.

 

most 400 and 455 ran 750 or 800 cfm from the factory.
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let me know what headers ,and mounts ya go with.

 

Will do.

 

Hey sorry no pics today ill have them monday. um one question? what kind of hp gain will i get from a new intake and carb?

 

If you already have a factory 4-bbl carb setup the increase will be marginal if anything at all unless you went with something like a high rise intake which will cause clearance issues with the hood. Like I said, Pontiac was real good about building things optimized right out of the factory.

The things that will increase HP and torque will be the compression ratio and camshaft. '74 engines were designed for regular gas and used only a 8.1:1 compression ratio. Swaping the heads for a set of 4X or 6X heads from a 400 will boost the ratio to around 9.5:1 when installed on a 455.

 

Ya thats what i have 4X heads but they were on the 455 already, will that change compression still? also im prob not going with the stock intake or carb. If i go with a Edelbrock PERFORMER AIR-GAP intake and a Edelbrock THUNDER SERIES AVS CARBURETOR what hp gains will i get?

 

There were different 4X heads. There is a secondary stamping on a little machined pad near the valve cover rail. 455's used 4X-1H heads with 114 cc combustion chambers. You need to find some 4X-3H or 7H heads from a 400 to bump up the compression. 6X-4 heads from a '76-79 350 or W72 T/A 6.6 400 would also work.

All Pontiac engines used air gap intakes right from the beginning in 1955. I've never heard of a Performer Air-Gap for a Pontiac. The Edelbrock Performer intake is made of aluminum so it will be lighter and probably slightly reduced the air charge temperature over the stock cast iron intake. Flow characteristics are about the same. You might see a 10 or 15hp gain.

The Edelbrock AVS carb is a glorified Carter AFB from the 1950s. I don't know anybody that has had any good luck with them. Sometimes they seem to work OK for a year or so and then they start acting up. There's a reason GM went to their own Quadrajet design in 1967. The stock '74 Quadrajet is an excellent design and will flow up to 750 cfm.

 

o ok i see i realy dont know a ton about pontiac engines. i think ill just stay with the 455's heads for now and maybe later down the road put the 400 one's on.

 

All new bearings, put the cam in, crank, and timing chain.

 

Also worked on the heads a little removed the springs etc. and soaked the pistons in carb cleaner to get the gunk off them.

 

What did you use for a rear main rope seal? DO NOT use the garbage fiberglass core EPA mandated rope seal that comes with gasket kits. It will start leaking within 100 miles if not sooner.

There is a new rope seal on the market within the last couple years made by a company called BestGasket with a kevlar core and graphite coated webbing that works very well. There is also the BOP Engineering lip seal that works well as long as the main seal groove in the block/cap is reasonably concentric to the crank centerline. Of course, if you have an original style New-Old-Stock asbestos core rope seal that will work just fine too.

 

Ya i know!!! dont worry i got the graphite one.

 

I was just looking at the head pics and noticed they have pressed in rocker studs. You sure this is a '74 engine? Pontiac switched to thread-in rocker studs during the '73 model year on 5/7/73. Maybe the heads were swapped out with a set of early '73 4X? You may want to check the secondary stamping and see what they are off of.

If you are not using a factory/stock camshaft you are going to need to have the heads drilled and tapped for thread-in studs and install some Big-Block Chevy studs and crimp nuts or poly-locks so the valvetrain is adjustable. The factory used a non-adjustable valvetrain with bottle-neck studs that put the valvetrain in a fixed mass produced clearances.

Really, the first thing anybody building a Pontiac engine should do is convert it to an adjustable valvetrain.

 

That BestGasket graphite rear main seal is the best thing since sliced bread. I had the engine out on my friends '74 Trans Am atleast five times trying to cure the leaking rear main seal before they invented that rear main seal. With the BestGasket seal it hasn't leaked a drop!

 

great thats good to know im not tryin to clean my engine bay every day.

 

OUTSTANDING!

I have put Olds/Buick V8s into third gens but not a Pontiac, not yet! This is my next third gen project when I get back home.

Be sure to take lots of pictures of the motor mounts in the car and the exhaust manifold fitment in relation to the frame and body. I would also like to see the firewall clearance and heater box issues.

Good luck!

 

It came out of a 74 but i could see that the engine was taken apart before, ill check the head #s to make sure. Is this good/bad if there from the older model? one more ? how much does it cost to convert to adjustable valvetrain?

 

Also i think i found the car its a 83 t/a hard top it passed inspection, so i can still drive it, and its 5 speed!! um one prob should i stick with the tranny in it now or convert to auto for the th400? will the tranny in the car now hold up to the 455?, cause manual would be fun. Also, tonight ill post pics of the th400.

 

These are some pics of the tranny it looks in good condition.

 

Today i put in the piston rings. And pollished the pistions. Next week i plan on putting the pistons in.

 

Still not sure if the heads are 73's i have found a website that will tell me what they are wallaceracing.com. ill check the vin num. next time i go in the shop. Also i am converting to the adjustiable valvetrain for fine tuning ill show pics when this takes place.

 

On the website i mentioned earlier it tells me they are 74 heads. It wouldnt matter any way because they have the same cc's 73-74 455 heads the only difference is that the 73 heads had adjustable studs and the 74 model didn't. What im going to do is instead of tap and dye for new screw in studs, ill put a locking nut on the pressed stud.

 

I think you misinterpeted some info the WallaceRacing website. Pontiac aways had a non-adjustable valvetrain. You have '73 heads as they are pressed in rockers studs. Its hard to read in your pic but I can make out a 1973 date code on your heads. All the '73-74 4X heads are basically the same with exception to the combustion chamber sizes and the screw-in rocker studs on all heads starting in May of '73. Previously only high performance applications got screw-in rocker studs from the factory.

The bottle neck studs are not designed to be adjustable. They usually fatigue and break off at the bottom of the threads if you try to use a crimp nut. With the press-in studs the stud will pull out of the head with a more aggressive cam. Pontiac only ran around .400 lift.

 

even if i have a mild cam they have a chance to break?

 

how long does it take usually to convert it? and how much do the new studs cost?

 

dens71ta is right on the info on your heads. they will either pull out, or snap off at the upper end. i replaced mine with some pioneer brand ones for a bigblock chevy, they are bigger, and stronger i think i paid 50.00 for them..and a good set of poly locks.
you will need to pull the pressed ones, and tap for the screw ins.
or find another set of heads.

 

you have picked the finest exhaust on the entire site.
it belongs to a moderator willie and his supercharged white 305 iroc.
finest ride on the planet.
but there can be only one.

 

Do they pull out or will i have to cut them, before I tap them?. Were did you buy them from? thank you for the price.
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I know when i first saw it i had to post it up. i looks clean, im not trying have a s****y exaust system, and im sure it adds hp. Plus im sure it sounds great!

 

Ditto what the other guys said about the heads. Now is the time to go junkyard crawling for some 400 4x or 6x heads, and then put the new studs in them.

Also, do you have a book around that tells how to build high performance Pontiac V8 engines? If not, you need to go to eBay and get one. There are many tricks that you need to employ on this engine to make it last, even if you are going to just beat it every once in a while. The rocker studs/adjustable valve train is one, and oil restrictors for the top end to keep more oil available for the rods/mains is another. There are also other little things that need attention for longevity.

I especially tell you to do this if you are on a budget. That book is going to save you tons of money in repair costs later!!

Good luck and keep up the good work!

 

85 TA w/455

Maybe this guy will have any info on fitment problems you run into.

 

he told me he had someone else do it for him.

 

Hey everyone dont worry im still here. Been busy, i wrestle for school so my life is basically at school right now. im trading in my 91 trans am for that 83 firebird i mentioned earlier, this will prob. happen over my xmas break. ill post pics of the car when i get it. Also i havent been to the shop lately and since im low on cash i havent bought thoughs studs yet or worked on the engine.

 

How does one change the CR with a stock pontiac engine? I mean, I realize its function of piston size/type, gasket, and chamber size, like every piston engine, but did they do like Chevy and use dished pistons to drop the CR? Or use different heads to drop the CR and stay with a flat top, like the big Mopars (383, 440, etc)?

I always hated that Chevy used pistons to drop the CR down, and not just the heads - or that they dropped it at all. I still don't see why they didn't stay at like 9.2:1 or 9.5:1... higher compression makes for more efficiency, which means it both makes more power and runs cleaner. Seems like that would make sense for an emmitions era motor.

 

Yes, Pontiac used difference size combustion chambers in the head to vary the CR. Due to the different heights of the combustion chambers between heads the length of the valves and springs are matched to that head number.

Pontiac used flat top pistons but '75-81 emission era engines have pistons with a big chamfer on the top ring land to prevent emissions from hidding between the piston and the cylinder wall. These engines run slightly less compression.

 

Bad news the car that i was looking at got sold already!!! so the search continues.

 

Do the old studs pull right out? i havent been to the shop for a while so i havent tried yet. and what size studs should i buy 3/8'' or 7/16''?

 

might of found a new car 1984 iroc.