If I were to guess, I would say you have a stock cast replacement pistons which are .030 oversized (4.280 bore)----the crane fireball cam is probably either a hydraulic or solid lifter cam that has a gross duration of 300 degrees and another guess on the lift of somewhere between .500 to .600 in. lift----it will run in a boat, as long as you don't try to run 5 miles WOT-----cam probably more duration than prefered, but should hit the bottom end of the power band depending what impellar is in the pump----don't think I would hit it with much nitros