Back in the late 1980's or early 1990's, I called the Chevrolet dealership in Daytona Beach, FL inquiring about historical records as I was doing some research on an early MO engine block that I have. I talked to several people there but got lucky with an older guy that gave me the telephone number of a lady that was retired that used to work at, what was then, Spence Chevrolet.
While she had no idea where any of the old records might be or if they even still existed, she did remember her early years working there. When I explained to her about me trying to make a Smokey Yunick connection to the engine block, she said she couldn't help me with that but she did remember some strange things going in regard to Smokey Yunick during those years. She remembered wooden crates coming in from Chevrolet to Smokey Yunick's attention. Spence Chevrolet would call Smokey's shop to come pick the parts up. Also, the invoices would have their dealer code with a dash 13 on them. Any invoices with a dash 13, she wasn't supposed to pay Chevrolet. She said it wouldn't matter if the dash 13 was there or not, because all of the invoices stated "Misc. Parts" in the description column and the unit cost was zero.