Lower unit needed. I believe this model originally had the jet lower but was replaced with a geared outdrive. The housing number is 1971-9760-C3. My question is, what is the difference between the 1971-9760-C1 and C3? Occasionally I'll see a C1 or C0 on ebay but never a C3. Also what other lowers could I put on this motor? Would a 4 stroke Bigfoot lower work? Lots of those for sale online.