Dave, good post. The only thing that hasn't been mentioned is individual gear ratios, 1st, 2nd, 3rd, and 4th. The final drive whether it is 3rd, or 4th will be 1:1, unless it's an OD. I don't have enough experience to make a comment as to which trans. If you keep the ratios fairly close to your 3spd and no big jumps between any gear you should be OK.

Larry

I don't own a vehicle that isn't old enough to drink.