You can figure that each inch in pitch dropped will bring you about 200 rpm.
A 16 from a 17 may not be enough. Imho, if you tested alone you want to
shoot for the higher end of the range so that when you are loaded up with an
extra thousand lbs of friends and gear you're still in the ball park.
Dropping pitch will definately help with the hole shot. A cupped prop may
provide more lift but when comparing props consider that cupping is roughly
like an extra inch of pitch. So a cupped 16 is about the same as a
non-cupped 17.

wrote in message
oups.com...
Nope, not cupped as far as I know, it came with the boat. And yes, I
believe this boat had a big block option.

So I drove down to the marina yesterday evening and did some WOT
tests.

3800 RPM's @ 36 MPH. It was increasing slowly so I think I could have
hit 40MPH @ 4000 RPM's. The previous owner would hit 38MPH top speed
but the fuel flow meter would indicate 1.9MPG. I was pulling 2.15MPG
and that tells me she had more left in her.

I thought I had posted I think it's over pitched. Now that I have
these numbers and plugging them into prop calculators I'm seeing a
16x14 should be the best option.

I'm going to give that a try when I get a chance. I think the engine
is working to hard to get up to speed. This would cause carbon build-
up, pre-ignition, and may even score the pistons and cylinders.

Dropping to that pitch should increase RPM's to the 4400-4800 power
band and the increase in diameter should help with torque. The more I
think about it the more it sounds like the thing to do.