The fact that the car has an unusual CID and engine number re: slant sixes (170, 198, 225) and that it's a midwest car makes me wonder if it wasn't a semi-factory backed machine-
Interesting thought, but the car's history - Bonneville, Lions and Riverside - plus the Devin "factory" being in California - would cause me to think it was more west-coast than third-coast. I suspect it just wound up here.
I've seen a pair of restored Devins at Road America. The production engine was a small block Chevy, and later, Devin produced a pseudo "kit" car based on the Corvair. I doubt if enough of ANY of these were built to qualify as a GT under current rules, and in this case, the modified sports class would not allow for the width to be altered.
Essentially, you'd be buying a Singer chassis set up for a slant six and the rather exotic remains of a footnote in sports car history.
Hmmm . . . now that I put it in those terms, it DOES sound interesting.