This 32mm Stainless valve. The stock valve seat will need to be removed and the seat #6149 must be installed. This valve is top quality and has a radius-type keeper groove. Fit 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. Use with seat part number 6149.