I have been asking around marinas and shops here and cannot come up with a good motor to place in my 1966 Starcraft (18 footer.) Some people are saying I need to find an old Merc inline six but others are saying a newer (1982 and up) four cylinder and outdrive off of a donor boat. How is the 3.0 and how fast will I be able to go? I know speed isnt everything but if I have to buy a new motor its gonna be a nice one (and hopefully a fast one.) I have read a lot of good information about both motors in question but I cannot get it out of my head someone told me the old inline sixes have problems. I appreciate any information-advice on this topic. Ideally the motor I get needs to have readily availible parts... I want to stay with Mercruiser because I like um'.