Joe Hull says:
Snip...
"Thanx Ed. I have a 64"Dia. x 76" pitch prop. It's supposed to be cruise
prop
that is designed for 190HP and 220MPH.  But you're right, it's too early
to
be cutting on the prop."

OK, here is where I demonstrate my ignorance...
My rough calculations, with an estimated 20% slip, says this prop with a
76" pitch, is good for 121 MPH with a 2.85 drive and 160 MPH with a 2.17
drive assuming a 6000 RPM cruise???
Where am I going wrong?

Bill Bradburry