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. Broader power band and improved throttle response when using MIVEC. For up to 9500rpm and 40psi boost Kelford Cams recommend valve spring KVS63-BTK.