i have a 72 cutlass supreme that i just put a 455 into and i was told that headers will not fit could you tell me what prevents them from fitting.any help would be appreciated. thx

 

You should be able to get a set of headers that fit.
For some reason suppliers have gotten the idea that the Cutlass Supreme has the engine offset or something like that. It is not true a big block Cutlass is the same as a 442 or a Cutlass S or an F85. The engine mounts are the same, the trans cross member is the same and the pinion angle is the same. If the engine was offset the OAI Hood would not fit a Supreme.

When you buy your headers make sure the flanges are nice and thick. Thin flanges will leak - Oldsmobile's manifold bolt pattern requires a lot of rigidity to obtain adequate clamping forces on the gasket.

 

I have headman headers on my 70 sx and have had no problems. They did have to be "massaged" a bit and the starter wiring had to be moved but nothing major.