If you want to put a 283 crank into a 327 block, you will need a small journal 327 block, or you could use a large journal 302 crank in a 327 or 350 large journal block to arrive at your desired 302 size. As for a 3.00 stroke crank hitting anything inside the case that a 3.25 stroke clears with the same length of rod sounds very strange to me. By the way, those little 302 engines in the Z/28s were to be respected and would scream. They are awesome!