@bartamos - Distributor, ignition coil, starter, and alternator are all 12V. My 216 Babbit was completely seized, and I replaced it with a 261 (235 with captain bars) from a 1961 Square body.
I'm grateful for the thorough help! Hubby has a 1968 Camaro that he's had since high school so this is our oldest (his second/my first) restoration. All advice is greatly appreciated! =)