"The original axle was replaced as part of the Olds drivetrain swap back when the car was still fairly new, but an accurate appearing clone axle is in it now."
This is also a very interesting mystery to me. WHY would the original owner swap in an Olds driveline early on ???? Is the 396 engine blown up and not usable ?? I really can't picture any stock Olds drivetrain from that time period coming close to even matching what this car was built with...