Very unusual for a customizer or coachbuilder to replace a modern, curved one-piece windshield with a retrograde dual-pane example. The prototype K-D had a two-pane windshield. Production cars did not.
Also, is this car covered in rust? Darrin's were fiberglass-bodied.
I suspect it may be based upon a run-of-the mill Kaiser, perhaps a Manhattan. The hood looks to be more-or-less like a '53 Manhattan's