I got some poly locks that busted on the machined part where they meet the rocker arm. I have a good stud girdle studs are 1.75 long screw .355 into poly lock witch is less than .4375 7/16. Ordered some 2.1" studs 2.3 would leave .900 threads above rocker arm. Nut wouldn't tighten up on them. Any body else ever had this problem?