Originally Posted by dba1062 (Post 4388087)

Kevlar382 is correct on the RPM's and speed as I owned his old 88 311. Another friend of mine with same boat ran 24p hydromotives 4blades. Slower top end speeds but better cruising speed. I still have the 25's Mirage non plus and thinking about selling them as I sold the boat. Keep them as a spares after I re-powered the boat.

Originally Posted by kevlar382 (Post 4387844)

I've had two 311s and if you are turning your props out like it came from the factory, I found that 4 blades picked the back end up a little to much and made them bow steer. Your X dimension is low enough that you shouldn't need a 4 blade. Both of mine came with 23s and I changed them to Lab 25s. Sorry it's been a long time time, but if I remember right my 1988 with 330s ran 66 at 4800 rpm. They both had 1.5 Bravos. If you want to run 4 blades, you might want to try turning them in.