This looks like a air valve stem just inside the rear door of my 76 Superior on the left side by the cot bar. Then only thing I could think of is for a air ride air bags but I don't see any air shocks under the car.
I think you are correct, most likely had air shocks originally.
This looks like a air valve stem just inside the rear door of my 76 Superior on the left side by the cot bar. Then only thing I could think of is for a air ride air bags but I don't see any air shocks under the car.