Hey yall, I just bought a 1968 Mark Twain 16-120 deluxe this weekend. I had posted a call for some help on the I/O motor forum but I don't think those folks are very talkative. I used to post on the outboard forum and there was always an answer to any question I had. Since I am just posting a general call for help I thought that maybe I could get some answers here. I need to know how to refer to my motor. Its a Mercruiser and it has four spark plugs on it but everyone is always saying they have an alpha motor or something like that. And I don't know what to call mine. I bought a Seloc manual and that din't help either. I am looking for specifics here and can't seem to find them anywhere. It says the motor number on the ID plate is 2421128. 