Dick, I expect some off-the-shelf header will fit, and as you suggested, it does not need to be a race header. I know this would be a good time to break into the LS engine movement. However, I am old and have so many years of experience with the first-gen small block and have many parts on hand to build one.
I have 5 grandchildren, and 3 of them want to test the waters, plus my daughter. Colorado will be a good, safe platform for them.
It is a "racer in the rough" just now, but I have been known to revive such projects
