Hello all- I have a Formula 280 SS that I just bought and need to get a set of props for altitude. Currently have 3x3 26P Bravo 3's and am only getting 3900-4000 RPM WOT. Wondering whether to go with 22P 3x3's or 22.5P 4X3's. The boat has 260HP 5.7's and the Merc Prop selector recommends the 4x3's. I have read that the 4x3 was developed for heavier cruising boats vs. performance boats. Mine kind of straddles the line. TIA.

I'd go with the 22 3X3's.

We developed the 4x3's because we had such bad cavitation burnning going on with the 3x3's when Formula started putting 500 EFI's in front of them. Long but good story. Probably can find the whole story written by yours truely in a earlier thread.

I like the 4x3 or 4x4 for elevation in the correct pitch. I think I have some 20's for testing.

Brett