A prop change can be done in about 3-4 minutes. You ca find videos on YouTube.
i assume it has an aluminum prop?
it doesn’t really matter much, but it would be nice to know which 4.3 you’ve got. There were two types available in 2010, the MPI (220hp) or TKS(190hp, 2 barrel carb).
So what we do know is that you’ve most likely got a 23 pitch prop and a 1.81 gear ratio. And you top out at 39mph at around 4K rpm.
Some people will say you should step down in pitch. I’m going to tell you to find out why you’re not making full power. I’ve got a 2002 4.3 2barrel (190hp) going through a gen 1 alpha with a 1.84 gear ratio. I’ve got a 23 pitch laser2 and a 23 pitch mirage plus. My boat is a 28 year old Wellcraft eclipse 196 (20’6 LOA). So I’m right about the same size as you. My laser2 hits the limiter and the mirage plus hits 4700-4750.
if my boat can turn these props, yours should be able to as well. since it can’t, the first thing would be to find out why. The first thing I’d do is figure out the age of the gas in the tank, and if you haven’t done so, change the fuel/water separator.
Whatever you do, don’t just throw a 19pitch prop on and forget about it, no matter how many times you’re told that’s fine.