Our Craw’s Racing 5/16″ Stem Billet Lifters come in different head sizes (1.020″, 1.100″, 1.250″, and 1.400″), surfaces (flat head or radius) and the stem size varies from .308 to .313 to account for engine wear. Please choose the correct lifters for you (sold in pairs). If you have any questions about available lifters please call us today!