For what it's worth . I currently have a 1973 318 with a 360 crankshaft in it. You have to have the mains turned down from 360 to 318/340 specs. I had the block punched .030 over so now the correct cubes are 350.96. I suggest you pay special attention to your pistons. Wrist pin location can be critical. DO NOT LET THEM TALK YOU INTO ZERO DECKING THE BLOCK!!!!!! That creates a whole nother problem.