I think the Saito 150 is the king of prop kickers but I wouldn't trade mine for the world. Mine is an early one with the black cylinder and chrome rocker covers that has higher compression than the newer ones, I also have an early .80 like that. Both will unload a prop at the slightest hint of leaness. The gray area that Damnathius mentions is very narrow on them. I appreciate an honest engine and know that if it kicks a prop, it's my fault. By the same token my YS .53 FZ can shed one in a hurry too.