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As you likely know already, Bill McKay Chevrolet delivered ZL1 #29 prepared by Harrell and raced by Grady Bryant also was one of Green Valley Bill Hielscher's Mr. Bardahl Camaro sponsors.
If any chance it's a Gibb Nova, what color is it as I don't think there were any Black ones?
Ken Hare of Euless TX raced a 427 powered Logghe chassis AMC called Ramblin' Rose so may be him, any more info or clearer pics?
Looking forward to whatever you find out, does the car exist?
Here's a recent link w/ Grady's ZL1...
https://www.yenko.net/forum/showthread.php?t=165058
~ Pete
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