I am currently putting a beefed up 455 in my '79 Trans Am, but cant seem to find any exhaust manifolds for it for a decent price, I can find 350 manifolds. I know 403 manifolds will fit on a 455, but what about the 350's? any help on this matter will be greatly appriciated.

 

The 350 manifolds will bolt up, but not breath as well as 455 manifolds. Yes, the factory dual exhaust manifolds are very expensive, something we have to suffer with being Olds fans! John

 

I know that funds are always an issue, but given the effort you're going through to get more HP, why do you want to restrict the motor with the small block manifolds. If this is a temporary thing until you can afford W/Z manifolds, fine. The only problem is that the factory manifolds are designed so that the exhaust pipe flanges are in the same place with each motor. In other words, if you use a small block manifold on a big block the pipe flange will be higher than normal due to the taller deck height. Just something to consider.

 

yes, funds are tight right now. I wanted to put the small block manifolds on there so that I can drive the car until I have the money to either buy the right manifolds or a set of headers for it. I ended up having to make motor mounts for it because I couldnt afford the $140 ones from classic industries. Thanks for the info, this should help me get it running temporarily.

 

Hello, it looks like you and I are looking for the same parts. Have you tried Thornton Reproductions? I am trying to find exhaust manifolds for my 455. So far, that is the only place I have been able to find any. If you do happen to find some somewhere, please let me know where. Good luck!

 

Any access to a salvage yard? ebay?
I can't believe a set of manifolds for a 455 are that hard to come by.
Even if they're single exhaust manifolds with a cross over...
just weld up a cap on the extra hole and run duals from the exiting holes.
I really think Joe is right...you do not wanna put 350 manifolds on a 455.

 

I am going to do it...........long enough to start fabricating fender well headers is all. Small block manifold is the only thing, except straight out horizontal headers, that will fit on the driver's side in my application.

 

Here is the web address for Thornton.

http://www.themotorcompany.com/Thorn...p-1-c-108.html

 

Call this guy he has a salvage yard of only olds parts he is in Tampa Florida.
Bob Anderson Tampa
(813) 932-4611

 

Call this guy he is in Tampa Florida and has a salvage yard of only olds parts
Bob Anderson Tampa
Home: (813) 932-4611

 

Note that the original question was posted in April of 2007!

 

better late then never...

I am on here more frequently and a lot of these old threads are really really informative so i for one don't mind


there is just soooooo much information....