I remember seeing a lot of custom Corvettes using Motion parts in the 1970's magazines like Cars Magazine , Hot Cars Magazine , and Vette magazine. Marty Schorr was the editor and featured many cars from the NY area.
Its a long shot, but maybe the car was in Magazine when it was first built
you can find a lot of these old magazines on ebay
here is an example
https://www.ebay.com/itm/Cars-Magazi...EAAOSwo3tasV96