I bought a set of heads that had already been machined for 7/16" Rocker arm studs. I don't think they were used much if at all. Unfortunately, the Comp rocker arms that I already have require 3/8" studs. If you want some more measurements I ca get them, I am just not sure if anyone would be interested. I am not sure who made them, but seem decent. I am looking for only $10 shipped to anywhere in the lower 48 (more if you are outside). A trade for some studs with 7/16" where it screws into the head, and 3/8" for the rockers would be even better!