AV&V compression release valves are easier to install due to their short thread section.(# JCR10A & JCR10B). You don't need to machine the heads as deep like if you were using O.E.M. style .

O.E.M. style also available (# JCR10D)

Ideal for stock replacement

Also their high-temperature resistant knobs are charcoal colored for a better match with black or silver heads.