I just bought this boat, it's a Skeeter Srada F-80 bass boat. It's 15.5ft with a 1986 90hp Evinrude. I took it out the other day and with a 13.25X19p aluninum prop I was turning 5400 rpm at WOT, not sure of the speed. Now for my question, the prop looks pretty bad and I want to replace it. I'm considering a 4 blade. I read that going from a 3 blade to a 4 blade you should drop down an inch in pitch. If I drop to a 17p what's that going to do to my WOT rpm? Stelleto makes an 18p SS should I consider that prop? Thanks