This listing is for a brand new set of screw-in rocker arm studs. Set includes 16 studs with shoulders. These are compatible replacements for the stock style press-in studs on small block Chevy V8 engines without having to machine the stud boss down on the head. Just pull the old 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.