Hi!
We used these engines in QM pylonracing here in Sweden in the beginning of the eighties.
We used the long Rossi quiet pipe and ran 80/20 FAI fuel (no nitro) and used Rossi 3.-5 glowplugs.
Props were 7x5 carbon or ...APC 7x5.
You don't have to replace the R/C carburettor to have it perform..we used it on ours... as the rules did not permit a venturi.
Expect around 25000rpm using a 7x5 APC and FAI fuel...no nitro is needed to have this engine perform.
Regards!
Jan K
Sweden
http://hem.passagen.se/airracing