COMP Cams 4514-16 Hi-Tech 7/16" Stud Diameter Rocker Arm for Big Block Chevrolet For Big Block Chevy Mark V and Mark VI applications Designed for ultimate strength and locking force Hi-Tech studs are good for higher RPM race applications 7/16 inches stud diameter and 1.900 inches effective length 3/8 inches base thread diameter and .750 inches base thread length