You can use the valve cover from your 216 on the 235. The other 99% of the world who are not stovebolt fans or judges will never know! Seriously, it depends on how you want to use it. If it is important to you to keep it stock then the 216 for sure. If you want a freeway driver, you would need at least a 235, redo the tranny and/or rear or add O.D., get radials and disc brakes.
