Small Block Chevy Stud Girdles W/Poly Locks 3/8" SBC 327 350 383 400 Race Car. Kit includes the double bar clamp style girdle bars made from 6061-T6 aluminum for durability and 7/16" poly locks. Girdle bars are anodized for a great finish. This kit is designed provide more accurate valve lift and timing by stopping rocker stud flexing. This kit is for standard stud spacing, and will NOT work with center bolt valve covers. Stud Girdles reduce flex and part breakage. Increased valvetrain rigidity helps minimize energy loss. Each set comes with aluminum stabilizers and poly locks. Complete with two rails and poly locks. We also have matching roller rocker in our store.