Ok I installed full roller pro comps shaft mounted rollers 1.52 steel rockers im using the polylocks for aluminum rockers, because the poly is to tall for valve covers so today the rocker stud snapped on the head right down to the nut where i got lucky and just zapped it off, qwuestion what could have caused this to snap overtightning the polylocks maybe...

 

Wow.... what size stud was this? There might have been too much stress on the bottom of the stud. Try going to a tall valve cover and relocate the altenator. Use the original locks. Definately not something I have seen before.

 

3/8 stu what does a taler valve cover have to do with them snapping i cut the valve cover so they can clear the rockers.

 

You said the rockers didnt clear the valve covers so you had to use the poly locks from the rollers to make them work. I say use the original equipment that came with the shaft rockers and go to a taller valve cover to clear them. Mixing and matching parts like that causes the type of problems you are having.