Thanks for replying Lou.

Horizen Hobby gave me different Specs for the Evolution .46 NT engine.
Bore=864''
stroke=.797''
displacement=7.65cc
It seemed to me using these figures that there was a significant difference in the stroke length and the displacement comparing it to other engines like the .46FX which had a displacement of 7.45cc and a stroke length of .772"using the specs supplied on this website. I realize that other factors also come into play such as prop size in determining the power vs speed ratio.

Thanks again