1987 ec 340 props?

[giff1]

I have a 340 express 1987 w/454s. I have 17x17 with cup props. WOT 4600 rpm, I cruise at 22kt @ 3100 rpm. Sea Ray specs list props at 17X18 With cup. Should I change my prop pitch? It seems I cruise at the right speed & rpm. Like to cruise faster. Whats best for the engines?

 

[NorCal Boater]

I wouldn't change a thing. WOT is in range. I would make sure the props are true and balanced. Look for a prop shop in your area that has a Prop Scan system or something similar.

I have an '89 340da and I cruise at right about the same speed (25 mph) @ 3000 rpms. My boat rides a bit different than your as I have v-drives and my props are 16.5 x 16.

You could also look into 4 blades. They will not increase top end but they are a bit more efficient offering less slippage. There are also 3 blade wheels available with as much surface area as 4 blades and they are as smooth and efficient and a bit less $$$.

 

[dpmulvey]

You are spot on with your WOT. Are you in the secondaries at cruise?

What is the distance from the hull to the blade tip? What is the distance from the leading edge of the prop hub to the hull?