[mreid]

When the rocker stud breaks, the valve closes so no real chance of a valve hitting a piston. The cam is pretty safe, too, but I agree with David, at least drop the pan and check out the crank and rods. The lifter body normally maintains position in the lifter bore when the guts are crushed and the lifter roller keeps its orientation to the cam, so unless there was significant pressure the cam should be fine.