Well here I go.. It Has a I-6 250 , and I would like to drop a 350 in it asap so what do I need to know what 350's can I find to put in to run this beast. There is alot of trucks here in my town that are broken down. So would a small block 350 from one of the early model chevy's work? I know it has to do with the engine mounts mostly so help me out  

A 350 from any pre LS1 equipped truck will work. You'll need to get a set of '69 small block motor mounts, probably a different throttle linkage hook-up, you'll also need small block pulleys and the arm to mount the alternator.

What trans does your Nova have?