Well, depending on what you classify as 'low compression', OMC used a variety of cylinder heads on the crossflow V4 and V6s, depending on the HP rating of the engine. ie, A 90hp had a head with a larger combustion chamber than a 135/140hp head, thus it was lower compression. Also OMC did offer a thicker head gasket as an optional service part to lower compression on some engines. Probably so the engine could run on the lower octane fuel that was common in some parts of the world
