Need help and info to help out my autistic son with his project

I'm pretty sure that B-Body HP exhaust manifolds will fit in an early a-body.

I haven't seen that. I have seen max wedge manifolds used before successfully, but that's it. If you have some pictures or info, please share as a good set of max wedge manifolds are almost as expensive as custom headers; HPs are a little more obtainable. I plan to continue with building custom headers, but if you could provide that info, it could be helpful to other members.