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

Welcome to the site.

Early As (66' and prior) with an RB, most people have a set of custom headers built or build them themselves. If you can find a used pair of Proparts, they will get you close, but will still need to be modified to work in an early A. I wish I had better news for you as I've always had a warm place in my heart for autistic kids, but there is really no good option for big block headers in an early A.

Looking at the link for my build won't help either as I never completed the headers and moved onto other tasks. I would suggest getting with racers in your area to find shops in your local area that will make custom headers. Unfortunately, they will be expensive. If I remember correctly, the last person I talked to said they had theirs made for $1500 and that's been a few years ago. Good luck.