I was able to pick up a Mirage + 3 blade 21 from blue heron...I believe it is a 14 3/4 diameter.
All the numbers are gps smooth water and a mile run through each rpm range. Boat had one person and approx. 40 gals. of fuel. No trim was used (motor and tabs).
Let me say this: instant response and torque on demand. Pulls hard all the way.
Motor is new less than 3 hours in the test. I have a feeling that I may be under propped when the stroker loosens up. Not by much.
rpm- gph- mph- mpg-
1000/ 2.1- 6- 2.8
2500/ 6 - 23.5 - 3.9
3000/ 9 - 29 - 3.2
3500/ 12.5 - 34 - 2.7
4000/ 14.1 - 42 - 3.0
One quick blast up to 50 @ 4900.
It seems when you hit 2500 rpm the mph from there on up almost = rpm.
Interesting to note that at 4000 rpm the mpg goes up over the 3500 rpm.
So if the grouper hole is 40 miles out I can be there (in good water)in 1 hour and use 14 gallons...or at 30 mph be there in 1 hour 20 minutes and use 12 gallons.
All this is subject to change...more weight looser motor, smoother bottom and so forth. However it is nice to get a baseline for the future.