Hi I just purchased a 71 Cutlass with a 350 with aftermarket headers. Will these headers fit on a 455 rocket as well?

thanks

 

No, they will interfere with things because of the deck height difference between the 350 vs the 455.

 

Well, depends on whether they are actually small block headers, or if they are big block headers installed on a small block.

The big block has a taller deck, so the headers end up sitting roughly 1" higher. Big block headers have longer primary tubes with a bigger drop to compensate. If your collectors are anywhere near the floor or anywhere near the correct place then those headers won't work very well on a big block.

Folks installing big block headers on a small block is not unheard of. They just look funny since they end up hanging so low, and normally are a major PITA to install that way.

 

First, header manufacturers wouldn't make different headers for BBOs and SBOs if the same ones fit both.

Second, every header manufacturer routes the tubes differently. The fact is that with some brands of headers, you actually can bolt SBO headers to a BBO and make it work. The fact remains that BBO headers typically have different pipe sizes and lengths to match the larger displacement.