The 850cc stage 1 cam is specifically designed for the 850cc engine. We don't sell 800 cams for the 850 like others do. Our stage 1 cam has bottom end to top end power. We focused on making sure the bottom end power was not sacrificed. Stage 1 cam has smooth linear power curve while still giving a 10hp gain. Made to work with stock valve springs. Peak power is at 8400-8700rpm. Drop in cam. Fuel tuning required