Re: alpha leg
As stated above... a 3.0 should be a 2.0 to 1 ratio, where the 5.0 is at the very most, likely a 1.65. So you would end up with an odd gear ratio, and you'd need a higher pitch prop. It can be done though. My father used his 1.81 ratio drive from a 4.3 when he changed to a 5.7. But he needed like a 27p prop, which he didn't have, and are not all that common. Later, he put a different lower unit on and ended up with like a 1.65 ratio. He was able to use a 25p prop then. Worked just fine.