I just bought a1972 seacamper that originally had a v8 outdrive in it .the past owner had a 1992 force 120 installed the mecanic was told not to by force but the owner wanted it done which i found out later my problem is when i give it full throttle or sometimes just over cruising speed it starts banging like its going to rip the transom off but everything seems tight if i trim it out till the props almost out of the water it seems to help alot i guess that would make sense since sometimes when i put it in gear it sounds like putting a stick in gear with a bad clutch