You should be able to find an original one as a good percentage of 216s are replaced with later engines. The only trouble is you may have to take the rest of the motor along with the valve cover. Speaking of that I have a 216 out of a 46 with a blown piston , but , the shipping would break you. Murray
The best one on fleabay was in Canada. $50.00 for shipping, though. Ouch!
