Whatever Brian, you don't even have a engine to test yet and already compairing it to another brand and make.
Jody didn't loose a thing with the new backplate, and you won't either.
What I get here is of no value to you to make a base decision on and really should be of no consequence to you.
8500 for top HP is with what prop and what altitude, HP is just a advertising gimmick that is basically a worthless figure.
When you get your engine, prop it to get the 8500 RPM's then tell us what prop your using. It won't be anything thats usable i'd be willing to bet on that. Plus the fact you will be out of the torque range of the engine. But I guess that dosen't matter.
Also 10 ozs of gas thru the engine is not enough to determine what my engine will do. Maybe after a gallon or two thru it then I can get some RPM's readings that count.