boatman1963
New member
i am replacing my 1969 merc 120 engine and drive with an 1974 omc 140 engine and drive. due to problems with the omc block though, i have to use the merc block and am wondering if the heads will interchange. both engines used the same head gaskets so i know the omc head ports will align to the merc block ports, but im wondering about valve clearances, both heads seem the same so even though there is a difference in the top of the pistons, i dont think there should be a problem. one thing i did notice though, the merc 120 used a steel head gasket and the omc 140 had a thicker blue head gasket so im also not sure there which gasket to use. anyone have any thoughts or input on this? thanks!!