So it was a used carb? Could someone have messed with it?

If you send it to Gary pretty sure he will charge you for a full rebuild. My experience with him on that is that won’t be cheap.

67 Coronet 500 9.610 @ 139.20 mph
67 Coronet 500 (street car) 14.82 @ 94 mph
69 GTX (clone) - build in progress......