Off subject but...
Adapt a pto pump to crank, proper threaded fitting with high pressure hoses (Like hoses for rear stability legs on a backhoe: as an example etc...) connected to a adjustable high pressure valve. Set valve so exceleration takes around 8-10 secs. Compare rpms run on track to area with fastest excel. on large faced tach without over-reving. If needed adjust gearing accordingly. When setting valve to allow longer duration of exceleration, set it where you can start and stop a stopwatch easily. Get a time from before and after the range run on track. Without moving valve make any change to engine whether on or off mower and compare times (even to determine which engine to use or save for a big event). Rate of excel in range run is all I look at, hp and trqe mean nothing to me when making changes. This may receive a reasonable amount of criticism, but it was intended for those that build their own or unable to afford high$$ parts and tweak what they have(no telling how much you have not being used). Can be used from setting timing to any mod.
If not sure if something is safe, it probably isn't. Wear safety goggles, takes a while to flush out of eyes if you have a leak.
Butcher.
