Ok, so im pretty positive now that my lower unit something in the gears is shot. So, i found a used outdrive in great condition. his is the same 302 but has 233 hp as were mine only has 188. I know the lower unit is identical Alpha one Gen one and would bolt up to my upper unit..... But is his outdrive gear ratio the same as mine ? As i know all the gear ratio stuff is in the upper not the lower. Basically can i bolt the used outdrive right up and go? Or just the lower unit? And if it is different ratio's would i have to do any modifications besides probably changing out the prop? Also does anyone know what my 1975 302 188hp mercruiser 888 gear ratios are?