Paul,
Sorry to hear your trouble.
Not knowing the cam specs is trouble. You need to check piston to valve clearance and valve springs for coil bind with a high lift cam.Check guideplate/pushrod alignment. I'm sure one of these do not have enough clearance, that's probably why you broke a rocker stud. Check the valve to see if it's bent, the rocker also. Without the cam card[spec sheet] you can't degree the cam in to make sure it's in the correct spot in relation to the crank.
Good Luck , check everything.
Perry.
