Edelbrock 6009 Rocker Arm Stud Kit Provides better rocker shaft retention and is highly recommended for use with Edelbrock FE heads Eliminates thread wear Includes stainless steel 2.09 inch intake and 1.66 inch exhaust valves to clear the 4.050 inch bores on a 390 CC engines Base thread is 3/8-16 Length of the effective stud is 2.348 and length of the base thread is 0.655