You nailed it. The good news is that it seems to be REALLY close to 1/64" (.015625) off still. It's looking like I'm going to get away with re-ringing and rehoning. Have to check the other pistons obviously so wish me luck lol. Got one of the exhaust valves out as well and it seemed good. No marks on the valve and no noticeable play. I plan on building the 360 sitting in the garage in a year or 2 since 400 ft/lbs of torque isn't as scary as I thought it would be in this car so if the 5/64" rings end up a few thousands off it should be fine for it's short life. Turns out not double checking tolerances is a bad idea when assembling an engine even when you're with people who have done it a few times. Who would have thunk it?