I work in a junk yard and recently had the oppertunity to install a 305 GM motor in place of 305 Merc in a 96 Bayliner. The guy took it to get it timed and returned with the boat. <br />The guy said he could not time because it had a car cam instead of a marine cam. My question is what is the differance or is there a differance? I am not looking for the rpms.