For what it's worth, turns out that the 165SR15 tires the previous owner bought before I purchased my '76 are all out of round. Those are new Nankang tires, and unfortunately the chain where they were bought (Les Schwab) only exists on the west coast (I'm in VA now). Buyer beware...
I'm looking for replacements (probably repros from Coker Tire this time) and a set of original steel wheels. Hey, anyone on the VA are have a set of *good condition* steelies? Trade you a set of Rivieras or buy outright