For your purpose, a super six is probably the best, but people now think they are made of gold. If you do find one for a reasonable price make sure you get everything, mainly the trans kickdown linkage. You could probably get a Offie manifold and a small 4 bbl (or 2bbl adapter) carb for the same or less money.
Stock exhaust manifold, but a 2 or 2 1/4 pipe, and free flowing muffler would not hurt. But before doing anything, I would check the basics. Adjust valves, then compression check, Maybe electronic ign, and adjust timing, maybe a little more advance. Of course check/change plugs, cap, rotor, wires, PCV (make sure the passage in the carb is clean), air filter. Drive it to see how it acts, stock, before doing mods.
PS: A friend here in Florida had one similar, and his estate was selling it.