You may have to be a little more patient.
Finding one in 2 days isn't quite that easy.
They pop up on the swap meet here from time to time. Start looking for older junk yards and in your local "shopper rag," stop and ask when you see a 67-72 truck rusting away in someone's yard. Start asking around and one will pop up before long.
They aren't under any pressure to crush these older vehicles other than the fact that price of steel us up and an Eaton Rear End is very heavy with little demand on the parts side. It costs several hours of no skilled labor to pull it or is can be crushed for $50.