302s of any kind are hard to find. The dirt track racers here have a new class that is restricted to 302 and 305 Chevy motors. Just about all the 302s around here have been scooped up. You can build one using a small main 327 block and a 283 crank. But I think I would build a medium journal 327. Any 350 block will work. I don't think you will need four bolt mains but if you think you do then a 350 block is what you want. You will also need a medium journal 327 crank. They are not hard to find. A lot of medium journal 327s have been rebuilt using 350 cranks. If you can not find one I can help you out.