Iam looking to put a 396 iback into my rs/ss (67) what year motors are the best or what will work. oh 4 speed tranny (st-10)

They'll all work. It just depends on what waterpump and accessories you bolt on. 67s use a short pump and have the alternator on the left side.

Only later 454/502 GenV and most GenVI dont have a mechanical fuel pump boss and also truck tall-deck blocks may cause problems with their additional height.

Any passenger MarkIV block will shoe-in!