This precision driver is sized for8.0 mm valve stems and0.500" (12.7 mm) guide bosses, matching the OEM style used on GM LS/LT, modern Hemi, Ford 7.3 “Godzilla,” and more. Gen III Hemi V8 – 5.7L, 6.1L, 6.4L Hemi (2003+) Chrysler/Dodge Identical (very close fit) 7.94 mm stem (0.3125″); ~12.6–12.7 mm guide Uses LS1-like positive seals; early Hemi applications often use a hat seal on intake Mopar seals: 8.0 mm stem Viton seals are available.
