according to my manual, QL77JC4 or L77JC4 gapped at .040 if used for slow speed operation, you do a lot of trolling. for high speed QL78V or L78V non adjustable
It refers to whether the engine is equipped with a fuel/oil pump that premixes the oil and gas before it hits the carb inlets.Your 48 special doesn't have OMS or VRO.