There are a few differences in the 216 and 235 distributors, mainly in the centrifugal advance numbers, and also the height of the caps and rotors used on early and late model distributors. When the electrical systems went to 12 volts, a taller cap and rotor and a slightly different height center shaft was installed to minimize the tendency for the high voltage to flash over to the breaker plate if a plug wire came loose. As long as the cap, rotor, and distributor match up, the complete assembly can be installed and will work in either engine. There's also a difference in the drive gear that is used with steel or cast iron camshafts.
Jerry
