what crankshaft could i use?

A floating pin rod has a bushing in the small end and the wrist pin floats in the bushing. The wrist pin is held in with snap rings in the pistons. Most 318's have a pressed pin rod meaning there in no bushing in the small end of the rod with the hole being slightly smaller than the wrist pin. The wrist pin is held in the rod by being pressed in to the rod. I believe a 318 piston is available for a floating pin setup.