Welcome to the site. Sounds like a sweet ride you have there. I guess I'm not sure what kind of help you're looking for.... a '72 340, while down a little bit from the '71 ratings, is still no slouch, and was about as potent a small block as there was in '72. It WAS a high performance option for '72.... 340's came in performance versions only from the factory, regardless of year; if it's just some performance upgrades you're looking for, pick up a Mopar performance catalog- you'll find plenty available!