I threw a rod on my '77 Merc 1500 (inline six, longshaft), with a 4-1/4" gearcase. I replaced it with a '93 Merc 135V6 (longshaft) with A 4-3/4" gearcase. The inline's gearcase is still good, will it fit the new motor? I have props for both size gearcases, and the gear ratio is the same, so...