I am almost ready to put my cadillac 500 into an 84 transam. Its going to be built pretty decent, but theres only one problem. I have to use the stock manifolds. I dont think theres any way I can make headers to fit. If anyone knows anything about cadillac engines, I was wanting to know how bad the manifolds would restrict power. With my ported heads, big cam, and edelbrock intake I should be able(I think) to push between 450-500 horsepower with headers. I would just like to know if, anyone has any thoughts.

 

like some other guy on here said "think of the motor like a garden hose" that would be like having a 1" hose going to a 1/2"... when you get some presure behind it it just doesnt flow good. you say 450 to 500 horsepower.... i would have to have some headers!

 

If anybody makes big block headers for a thirdgen, you can get a new exhaust flange and cut the one on the headers off. Then weld the new ones on. I don't know where to get them, though. Ive got a friend putting a 500 in a 72 chevy truck. I think there's a Cadd motorsports or performance or something like that. It would require some measuring and welding skill, but it can be done.

 

check out headers by ed, hes a little expensive, but makes the best headers around and can custom make a set to fit nicely, but full lenths and 3rd gens do NOT mix well

 

are you sure your going to get those numbers in hp? more likely to have those in torque.