Otto has got the right car! No wonder he was champing at the bit...
Yes, it's a Chevrolet Corsa, and according to my book "Chevy toyed with both front- and rear-engine layouts for Corvair 2. Badged 'Corsa', this full-size mock-up from July 1965 was obviously front-engined and maybe front-wheel-drive too, as its profile implies. This same general shape would later appear on some Brazilian GM cars. Reduced width and overall size suggest Corvair 2 may have originated as a subcompact companion to the existing Corvair, but it may also have simply been a study toward something for GM's European or South American operations."
Note - Corvair 2, not 3!