This valve is .070 longer over all lenth is 2.650, head measures 25mm, and it has a radius-type keeper groove. This Valve will not work with stock retainers. Will fit stock 5.5mm valve guides. Use ARC# DJ-1047 retainers for 22 or 26lb springs, or DJ-1046 retainers for 36lb spring. DJ-1051 lash caps are recommend.