Headers
At that level, a set of custom Hedman Hussler fender well headers may be worth looking into. The custom sets I’ve seen look great, but some of the latest reviews I’ve read on them have been equally good and bad. It wouldn’t surprise me if it could make use of 2-3/8 primary tubes and 5 inch collectors. I just noticed that TTI doesn’t make any A body headers for the Indy RA heads, either, so it’s probably going to be a custom affair.