Model max mph = (engine max rpm X propeller pitch) / 1056

Note that this is max reachable speed, for an ideal condition in which the propeller does not slip respect to the airstream.
Real or aerodynamic pitch depends on the AOA of the prop blades, being zero for static tests, and max for diving flight.

Hence,

Model max mph @ 8 pitch = (14,200 X 8) / 1056 = 107 mph

Model max mph @ 8 pitch = (16,920 X 8) / 1056 = 128 mph

All these theoretical calculations indicate that for speeds higher than 128 mph, pitch 10 is the key for your Revolver.
Pitch 8 and a 30 degree dive cannot move your model faster than the speed you have measured.
I believe that having so much available power, and willing to push the speed envelope seeing no engine puffing, 13 x 10 is your best prop, as confirmed by this thread:

http://www.rcuniverse.com/forum/m_94...tm.htm#9426330

That 13 X 10 would load your engine in static test just as the 14 X 8 did (8500 rpm).
Did you measure in-flight max speed for the 14 X 8 that you statically tested?
As you know, the 13 X 10 will give you more top speed than the 14 X 8, but it would be less efficient for take-off’s.

More theory, if you don’t mind:

• Check attached nomogram to select pitch based on speed.

Full article here:

http://www.rcmplans.com/issues/reque...011990-1-1.pdf

• Clarence Lee’s review of your engine:

http://www.rcmplans.com/issues/1999/...-081999-1.html

The static rpm results per propeller were:

13 x 6 - 12,500
13 x 8 - 10,400
13 x 10 - 9,500
14 x 6 - 10,900
14 x 8 - 9,500
14 x 10 - 8,400
15 x 6 - 10,200
15 x 8 - 8,100
16 x 6 - 8,300

• A good calculator for static thrust:

http://adamone.rchomepage.com/calc_thrust.htm

• For a 30 degree dive, a force equal to half the total weight of the model adds to the engine thrust.

Additional thrust force = sin 30 X weight = 0.5 weight
Necessary wing lift = cosine 30 X weight = 0.86 weight (then wing AOA and drag get reduced)