Boat Motor Needed

Gentlemen,
I posted this on the boating forum but it doesn't get much visibility, so I'm going to try it here. I am in need of a 4cyl chevy motor for a 1972 Aristacraft 21 ft boat. I'm trying to restore the thing and the motor is just plain tired. Does anyone have an old boat they are junking that they would like to sell the motor? I am understanding from my friends that these motors have "issues"? Any comments or help wowuld be appreciated.