I need to do a complete rebuild on a '95 Polaris 300 4X4 2-stroke engine. This engine had the plastic oil pump gear. It ate the plastic gear and the top end seized up. Bottom end has a lot of runout on the clutch end (.015") and main bearings sound rough. As an option, I am considering a used bottom end or even a used motor. I need help determining which 300cc engines are compatible with the '95. I thought I could go by the crankcase part numbers, but this model is so old, most online dealers don't list the P/N for the engine cases. I know that it is a EC28PF01 model engine. Just moving to a '97 model, the engine model# changes to EC28PFE01. Any help would be appreciated.