[Rick Parker]

Does he recall having any repair or service work done on it at any Dealers or garages that may still be around, sometimes they are notorious for keeping old repair records, or even insurance companies records may be available. Remember the dealer or garage record were not computerized at that time, all records were on hard copies of RO's (repair orders). You'll also have to potentially talk to retired folks (if available) who may have worked at the facilities. You might even pursue where he bought tires locally.
Good luck.