FOUND IT!!!! This is getting interesting
I found this in the book "Corvette: America's Star Spangled Sports Car"
"
Hooper's sinister-looking black coupe made a 20.5 second pit stop for thirty-one gallons of gas and a quart of oil, then held off a late race challenge by Jay Hill's Porsche RSK to take the victory for Chevrolet"
I found the following in the Leffingwell book: "
Bob Bondurant, Dave McDonald and Jerry Grant drove the three cars, a silver , a white and a bluew coupe, out from the St. Louis factory to break them in while another car was trucked out earlier"...
.."
the fourth Corvette, entered by Mickey Thompson and driven by Doug Hooper won the race"
From this, we can conclude that Dick Thompson did not raced in that event, and probably it refers to Thompson (Mickey) the owner....
The car was black. End of the mistery, my job here is done, I'm outta here

Thanks,