I went into my local auto parts store and asked for a mechanical fuel pump for a MkIV big block chevy and was told that unless I got the right one, I would "break my camshaft". My engine is about an '88 model 454 out of a pickup truck that ran an electric pump.

Question: Are all fuel pumps for the MkIV style BBC's interchangeable? Could I order one for my '65 biscayne or a '73 longbed and get the same thing?

I was only 95% sure that all MkIV fp's are the same so I left the store without one.