The valve cover is an easy place to start. A 230 or 250 will have 6 bolts holding it on. A 235 will have 4.
A 230 or 250 will have the distributor all the way to the front on the pass. side.
235 is midway back on the pass. side.
And the side cover(pushrod cover) is 2 pieces on a 230/250.
235 is one piece.
Seein as how the motor is in a 63, its most likely a 230/250