My yellow sprint revs to 7300rpm and has max power on the wheel of 139hp. Hans can state this but he still doesn't know why
Maybe i will tell him once the secret of a good STD engine
STD mahle pistons.
STD hs6 carbs
BELL sport exhaust
Lightened std flywheel
Lightened std rods
All std and not new but good enough to had it re used.
I think in your case it's the ignitiontiming and it's importand to have all balanced very well. All rods the same weight and the rotating and translating weight also in balance. There are also lots of different clutch covers from aftermarket suppliers and these like the LUK or Valeo are much (1,5kg!!!) lighter than the original heavy ones.