I have a HEI out of a six banner will this fit a chevy V8 if i change out the cap?

No way, you need one from a V8. big or small block will do. Make sure you get one from an early model,70's. These are the ones with only "two" wires. The early/mid 80's have 2 groups of wires, won't work. Good Luck..Rick.

Thanks for the info