I searched for about 2 hours and i still dont have an answer, some say you don't need to machine the rockers for arp studs and others say you do. So what is it?
Some valve covers you have to grind more on than others, it all depends on where they are made, india, china, USA. If you dont machine them down you might not be able to install the washer cause the stud is not sticking out enough. Just take the time to machine them and do it right. I did mine and it didnt take long with a sharp end mill.
arp you have to grind. no way around it. unless you like your nut with only half the threads engauged. machine shop should do it for 50-60$. i takes less than an hour.
I tried to run mine with just the valve cover ground out. First I blew a head gasket and I had oil leaks on the valve cover gaskets. I bought a mill and the first project was to mill my rockers. Best thing I ever did.