crank shaft

Hello, Looks like I need some more advice. I called Summit up to get some headers for a 1970 Cutlass supreme with a 455 and was told that there's a problem installing them on a 455 due to the height and offset of the engine. They said they would sell me some headman headers and I could try to make them work. Can anybody please tell me what headers will work on my car?
Thank you. Mike

4speed455

There is no offset on a supreme compared to a cutlass/442. Any headers that will fit a 70 cutlass/442 with a 455 will fit a cutlass supreme with a 455. Same thing with the 350.

oldstata

x2

crank shaft

Wow, wonder why they would tell me such a stupid thing, I know I have seen headers on 455 engines And I have a 350 in it now with headers

crank shaft

That you!

oldcutlass

Because the tech notes incorrectly say so.

crank shaft

Thank you! I hope this will be the last issue I have with this swap, we haven't started it yet. I'm just trying to buy most of the big parts before we start it.
Thanks guys!

joe_padavano

This has been an ongoing problem with header manufacturers for decades. I have personally contacted several manufacturers to try to get this cleared up, only to be blown off with a form letter email each time. No one knows where this misinformation came from, but it seems to be impossible to kill it. As noted, simply get headers for the same year 442 and ignore the footnotes. As for these phone tech help lines, if it isn't a Chevy, don't expect useful info.

joe_padavano

If you are swapping a 455 in place of a 350, the first thing is, do NOT get "455" motor mounts unless you are also swapping the frame mounts. Personally, I'd same the money and simply use your existing 350 motor mounts (Anchor P/N 2261) and frame mounts with the 455. This will put the crank centerline in exactly the same place as it would be if you had used the 2328 motor mounts listed for the 455 and switched the frame mounts. Either way, the exhaust ports on the 455 will be in exactly the same place and the headers will fit the same either way.

crank shaft

Thanks Joe, if useing the350 mounts I heard the engine sits higher and will effect air cleaner to hood clearance. But if crank centerline is the same, I think cylinder height may be an issue.

joe_padavano

The carb and air cleaner are higher because the whole engine is an inch taller, not because of the mounts. Yet more bad info onto the web. The 455 was factory available in this car. Hood clearance is not an issue with stock-height intake and air cleaners.

FYI, the motor mount and header questions come up here about once a month. Search is your friend.

Fun71

Trust us when we say it is not an issue. As Joe stated, these cars came from the factory with 455s, and folks have been swapping 455s into original 350 cars for over 40 years.
You are correct that the heads will be higher, which reduces the clearance between the valve covers and the master cylinder and AC box. It's no different than a factory 455 car, though.

crank shaft

OK, Thanks guy's I will stay with the 350 mounts. I want to put a Edelbrock air gap intake manifold with a Holley carb. Do you know if this will work with a stock hood?

slam1918

American Racing Headers, Lyndinhurst, LI ...I'm using their stainless header that bolts right up no mods necessary. You must switch to the compact starter. They don't hang under the car as deep as the hookers I had on previously which had some lovely dimples from bottoming out.

crank shaft

I see what ya mean,car also looks nice underneath. Was she a frame off?

R-body_mopar

Many years ago, I had a 1970 442 post coupe with 4 speed 455, and had no problem with Hooker headers, except for the fact that they were too low, and had ground clearance problems....and the fact that they rusted away in the salt belt here..... I guess I should have spent the extra bucks for stainless....

crank shaft

I live in the salt belt also, I will take that advice and get the stainless. Slam said to go with the American headers. I wonder if summit has them. I will give them a call, thanks all!
Mike

slam1918

I have owned the car over 15 years. The guy I bought it from restored it back then but not frame off. Powder coating had not been invented yet so he used an orange epoxy primer which I curse him every time I'm under the car. Little paint flakes come off. I etch the metal & use a marine monopoxy with brushing liquid to hide the orange primer. I recommend listening to the mufflers before you buy. I have the 2 1/2 flowmaster kit for Olds which fit fine. the 2 1/2 exhaust tips are from pypes. I'm getting used to the sound. problem is the flowmaster seems to take away that "olds" sound where the old 2" dynomax kept it Olds . Don't get me wrong, it'd deep, throaty, not too loud, but the other day I pulled up alongside a 70 SS and it sounded very similar.

crank shaft

I'm running the same climate system on my olds but its a 355. I have never heard of dynamic mufflers but I will check into them, thanks slam!

joe_padavano

Not dynamic, Dynomax. They are made by Walker.

crank shaft

Thanks Joe, my phone sucks it likes to change words on me

Fun71

Ah yes, the Auto Incorrect feature.

dc2x4drvr

x2, pricey, but worth every penny. Smitty275 is a vendor..

70cutty

Holy crap, $1000 for American Racing headers. Damn.

crank shaft

I like that, the auto incorrect feature, yep thats on my phone. Wow are those headed made of gold?

slam1918

when you go from a mass produced piece of metal to a custom made chunk of stainless your gonna pay the price. you can check Kooks, I see some of the guys use them. I think they are similarly priced. Ebay has some China made ones but I know from the marine industry the stainless out of China just blows!!! ya get what ya pay for. the hookers I took out were complete rust & flakey. I live near the beach but the car lives in a garage with a dehumidifier.

crank shaft

Thanks slam, I will invest in a good set of headers, I put a street fighter trans in over last summer and took the left header loose and it was a pain to reinstall, good point. I done wanna go through that again, also I feel your pain with the orange primer. My car is green and they used yellow primer, if I get a stone chip it stands out like a sore thumb, as soon as I get the car off the lift I will post some pics!