There are some good comments regarding this subject. But there are also some important issues to deal with as well
1) type of prop, thin blade, wide blade,stiff blade etc.
2) Mfg of the fuel(gas) and the oil as well
3) ratio of oil to fuel
4) location of where the engine is run and what altitude.
5) ignition, magneto or electronic either throttle coupled or auto advance.
current hp numbers are a numbers game. what you must do is question the mfg of the engine on just how the hp numbers were obtained. with what prop,fuel/mix etc.
What you want is Peak Torque Horsepower, and the only way to get that is via a dyno.
As a note, Nicklesil is a trade name for Mahle Cylinders, not the engine mfg.
Also applies to Sach, Husky and at one time Stihl.

Use the combination that works best for your specific application.

I have a 20# Suchoi on a TS52 swinging a 24X8 @ 6100 With a TNC Tach on 87oct @80:1 Amsoil
And it seems to do everything I want it to do.
But thats my style.