I have acces to a bare block from a 65 chevy. I think that it is a 250 or 292. It is literally a bare block. But we are in the same state and this might interest you. It would be available for free, my friend bought it years ago to rebuild and put in his 65. Anyways, I hope it is just a head gasket. If you are going to get a goodwrench motor just go to a dealership, or get a "Summit Racing" magazine, they sell a variety of GM crate motors. Good Luck.
Kyle