Let me ask the right ques.the previous owner had a 350 engine in the car.changed it to a 455 engine.he reused the 350 exhaust manifold on the 455 engine,not a good thing.he installed a whole new exhaust system using the 350 exhaust mabnifold gm #38001.i just purchased w & z exhaust manifold.would the pipes bolt up to the new w&z heads with no problem or do i need adapters.

 

I am not sure the bend in the pipes would be a perfect match to bolt right up as the 350 manifolds did. I would say its going to be trial and error. A muffler shop should be able to fix or correct things if need be.

 

The issue you're looking at is the W/Z manifolds are longer than the standard manifolds. The pipes should bolt up just fine, but they will stick down a bit too far. A muffler shop would be able to shorten them but the problem would be getting the flare right so they can be re-attached to the manifolds. You'd be better served getting new down pipes.