Valve head measures 32mm, total length is 2.650" (+/-.004). The stock valve seat will need to be removed and the seat #6149 must be installed. Top quality stainless steel with automotive style keepers. Fits the 5.5mm stock valve guide. Use ARC #DJ-1047 retainers for 26lb springs or DJ-1046 for 36lb springs. DJ-1051 HP lash caps are recommended.