Prop Sizes ?
 

Hello All
I have a 95 272 barchetta, its a 7.4 385 hp FI.
It has a 15 1/4" x 21 pitch 3 blade prop. It seems to work fine, However its a little nicked up. I want to buy a spare, and then get this one reconditioned. If I change to a 4 blade, what would be the correct size, and where to buy?
thanks