This listing is for 16 brand new set of 3/8 Top threads, 7/16 base screw-in rocker arm studs. Compatible with small block Chevy V8 engines. Designed to replace the stock style press-in studs without having to machine the stud boss down on the head. Just pull the old press in studs and tap the holes to 7/16-14 coarse threads. 3/8-24 Fine thread TOPS and 7/16-14 Coarse thread Bottoms. 2.325 Overall stud length. 1.600 Stud height 0.725 Screw-in thread depth.