TommyTheCat

Hi folks,
I am looking to install some headers on my 1978/79 350 5.7l - Motor is completely stock on the outside
I am wondering if anyone can tell me if the exhaust manifold/header bolt spacing and pattern for the 78/79 is the same as the earlier 70s 350 Olds.
it looks to be from what I can tell in pictures

Most of the headers I see online are for pre 78/79 and im wondering if there is a reason for that, other than those years being less desirable being they were the smog motors.
Is the bolt spacing different ? or does nobody see the value of hotrodding the 78/79 motors ? =D

any info would be appreciated

old80cs

I have old Dynomax ceramic coated headers on my Olds 350 in my 80' Cutlass Supreme. Most listings for headers in the 78-80 Cutlasses are for small block Chevy's, be careful that you order headers for an Olds V8. The small block Olds 350's all have the same bolt pattern, it's the application that matters to be sure they will fit your car.

TommyTheCat

AWESOME! thanks a lot for the input.
I assumed that the bolt pattern was the same. My motor is in a 53 Rocket, so the only real issue is if the drivers side header will clear the steering box, which it likely will.
I just wanted to get some knowledge from one of you guys before I put some money down. I trust the people here more than I would the support of whoever is selling the part online. lol
And I have definitely seen the listings for small block chevy stuff under olds. Its obvious to tell the difference , so they cant fool me =D
Gonna go with a whole new header and exhaust setup as my yearly treat for my baby
thanks again for the info ( i see youre in Mass as well ) maybe see you around =)

joe_padavano

Every single second gen Olds V8 made from 1964-1990 has exactly the same exhaust port spacing and bolt pattern. While not your question, the 7A heads used on the 1985-1990 roller cam 307s have smaller ports and earlier headers or manifolds won't seal properly, but the bolt pattern and port spacing is still the same.

TommyTheCat

awesome! Thanks for the info.

they look to be the same from what i could tell i just wanted to make sure.
thats one thing I like that Olds did and thats how they made so much of their drivetrains very similar throughout the years. So swapping and upgrading is extremely simple.

the motor I have is never going to have the potential of the early 70s blocks, nor do i need it to.
Im just doing some slight upgrades to it since its a very healthy and relatively fresh rebuild.

olds 307 and 403

Actually a member on the G body site got the Thornton manifolds to seal with gaskets. Do some measurements, there are a few options out there with considerably different routing.