Bill Riley can lay claim to having one of the coolest fathers in our sport. His dad, Bob Riley, has seen his designs win the Indy 500, sports car championships, and countless other accolades over the last 50 years. And from those wide-ranging projects, some cool promotional materials have been generated, including an internal documentary on the front-engine Ford Mustang GTP car that made its debut late in the 1983 IMSA season at Road America.

The short feature, which runs almost 30 minutes with raw footage tacked on at the end, sat forgotten in a drawer for four decades until Bill Riley happened upon it over the summer. Converted from VHS cassette tape to digital, everyone from former Ford boss Walter Hayes to Ford Racing boss Michael Kranefuss is interviewed in the celebratory production.

“Other than a few people back in the day, I don’t think anyone has seen this,” Riley said. “It’s a cool snapshot in time of this project my dad was a big part of.”

Drivers Bobby Rahal, Geoff Brabham, Klaus Ludwig, and Tim Coconis are also featured, along with Bob Riley – taking a swig of champagne towards the end. A young fabricator by the name of Gary Pratt, who would go on to form the almighty Pratt & Miller outfit that runs the Corvette Racing program, can also be seen in the video.

Long before Don Panoz found success with his front-engine roadsters, and a lifetime before Nissan tried and failed with its front-engine LMP1 concept, Riley’s Ford Mustang GTP and its tiny 1.7-liter turbo four-cylinder engine set the standard among rear-engine prototypes on its incredible debut at Elkhart Lake.

Take a trip back in time to the formative years of IMSA’s GTP class, courtesy of a stellar find by the Riley family…