Hi I have a 1989 Sea sprite mark II with a 170hp mercruiser 4.3 liter v6 engine. It has an alpha one outdrive s/n oc650434 gear ratio 1.84:1. I picked this boat up for cheap Its lower unit is pretty much toast. The previous owner did not winterize the boat properly and the lower unit cracked at the Bearing carrier assy. My question is this I have another alpha one lower unit off off a mercruiser 3.0l 4cyl s/n A388992. Can I interchange the two lower units to make a good running boat. I've heard the gear ratios are different but believe the gear ratios are only concerend with the upper part of the outdrive. The sea sprite has very low hours since overhaul on its engine and i do not want to cause any engine problems by swapping lower units. Can the two lower units be swapped or what would I need to do to make the 4cyl alpha one unit work on my 6cyl. Thanks in advance for any info you may provide.
