Product Description Specifications With a 7/16" base thread and a 1/2" rocker thread, the Hi-Tech stud features rolled threads for maximum contact and a ground-flat top for accurate valve adjustment. This stud set has a 1.900" effective stud length with a .735" long base. Category: Engine Components>Valve Springs, Retainers Core: N LTL: N MPN: 4543-16 Proposition 65: Y Special Order: Y