Ha, Covid Hut, that’s a good one! Lol, me too 1st gens rule!
Last winter I decided to mock up a big block/manual trans in the subframe with correct motor stands, mounts, trans cross member and such. The only thing that I noticed was the old 6-cylinder clutch linkage mounted differently, no problem we’ll just punch and tap a new hole to secure it correctly. This original 67 subframe was born with a 6-cylinder manual, then upgraded to a small block automatic before me.
Hooker headers fit quite well at this point also. Just touching the steering box and the right upper control arm.