The ultimate 272° on the market. Dyno proven to be the best available to date. High lift profile design with high rpm valve train stability. Suited for 450-700hp high rpm racing 4G63 engines. Suits turbo sizing in the 54-68mm range. Great with E85 and similar ethanol blend fuels. For up to 9500rpm and 40psi boost Kelford Cams recommend valve spring KVS63-BTK.