It's not that the cam is too big, it's that the rest of the valve train isn't properly set up. Coild bind, the correct installed height of the springs, sweep across the valve stem all need to be verified, or you will keep breaking parts.
That is both no fun, and expensive! Time for a trip back to the machine shop to figure out W T F !
That is both no fun, and expensive! Time for a trip back to the machine shop to figure out W T F !