Thanks guys, glad you enjoyed them. Here is one more that at first glance doesn't appear to be related, but I suspect it is. This is almost certainly the 1969 Kar-Kraft prototype Mustang fastback, nearing completion, but still without paint.
Randy Hernandez sent me this photo but didn't have any info to go with it. But he also sent a small series of photos showing this car in its just completed stage, which you would have seen before, in its Shelby blue colors and American Racing Torq Thurst-style wheels. The series of photos Randy found in a brown envelope, which was dated December 14, 1968. So the prototype was completed by December 1968.
The 1968 Trans-Am series ended in October, and the above posted '68 Shelby car that became the test hack was trialed after the season finished.
The '69 fastback pictured below features an interesting wooden buck on its hood, that is neatly shaped to the curvature of the hood. My guess is this photo would have been taken at roughly the same time as the photos of the '68 test hack, with its tall plenum sticking up through the hood. So I wonder if Ford/Kar-Kraft flirted briefly with the idea of running the tall plenum, and a large hood scoop, possibly with a Naca duct in the front, as seen sitting on top of the wooden buck.
Maybe I'm way off the mark, but its still an interesting conversation piece.