1972 Demon 340 engine mods

I always figgered if I was around in 72-73 and bought one of those detuned 340's that I would just swap a earlier cam and top end over onto the bottom end and be done, Weekend job wrenching and tuning.
problem with this idea is all 1969-73 340s had the same cam. the lower compression was .100" shorter pistons. and 1971-3 had bigger carbs