I'm thinking of doing the Boss 289 "upgrade" to my 66 289 that @22GT told me about. It's listed on Mustang Barn's tech info page. Question is if I machine screw in rocker studs what size do I use? ARP makes 4 different 7/16 studs ranging from 1.9" installed length to 3.0' installed length. I looked thru my workshop manual and couldn't find any listing to the installed height of the press in studs, so nothing to compare too.