Anybody use the year one hp exhaust manifolds ?

Skeptical I am. Anything can be made to work but! What other issues to deal with!

Jim knows his stuff but a short response he gave.

Probably because I have answered this question 500 times in the last 20 years. Yes, there are fitment issues, but we're building big block A-bodies with non-stock parts. Also every car is different. You won't like the clearance issues on my Barracuda, but it all works.