I have heard that a Spoon Sports modified F20c can do 11k reliably. The engine has a very long stroke for its size, and stock, the piston speeds are already hig

I have heard that a Spoon Sports modified F20c can do 11k reliably. The engine has a very long stroke for its size, and stock, the piston speeds are already higher than almost any other car engine, so that it can spin as fast as it does is pretty amazing. Motorcycle engines, however… Some of those are 14-16K stock.