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1969 L88 Vintage Corvette Tours the Milford Proving Grounds

Retired GM engineer John Heinricy tours the Milford Proving Grounds in Fabulous Restorations’ L88 Corvette

Walt Thurn Aug 7, 2018
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John Heinricy was inducted into the National Corvette Museum Hall of Fame in 2014. His selection was based upon his successful 38-year engineering career at General Motors. He joined the company in 1970 and retired in 2008. He summed up his job experience by saying, “Where else could you find a job that lets you play with cars all day?” He started his work at Chevrolet as an Experimental Test Engineer at the Milford Proving Grounds. He was promoted to Manager of the Front Wheel Drive Development Group and continued gaining additional job responsibilities during his time with the company.

In 1984, Heinricy was encouraged by Dick Guldstrand to obtain his competition driving license from the Sports Car Club of America (SCCA). He took his advice and with no support from GM, received the coveted National Competition driving license. John began racing Corvettes for the Morrison Motorsports team in the mid-’80s. He went on to become an accomplished competition driver, accumulating multiple racing championships. He is known as “Heinrocket” among his friends and fans. During his time with GM, he helped develop the C5-R Corvette and CTS-V Cadillac. Both of those race cars went on to win multiple sport car championships in the American Le Mans and World Challenge racing series. His last position with the General was Director of GM High Performance Vehicle Operations (HPVO). Between 2001 and 2008, he and his team developed, built and tested most of the corporation’s high-performance products, including the Cadillac CTS-V. Much of his team’s HPVO product testing took place northwest of Detroit at the mystical Milford, Michigan, proving grounds. One of his lasting accomplishments was his development of a three tier (level 1, 2 & 3) engineer certification driving program. Its purpose was to confirm an engineer’s driving skills prior to any rigorous vehicle testing. Only level 3 certified engineers were invited to do HPVO vehicle testing at the 12.9-mile Nürburgring test track in Germany. John has driven over 1,000 laps around this legendary German track. He has set several production car track records there in GM vehicles (Corvette, Cadillac, Camaro and Cobalt). Though retired, he still actively races, tests and works on improving various automotive products. For more information on this GM legend, go to www.heinrocket.com.

We caught up with John at a National Corvette Restorers Society (NCRS) Motor City Regional in Detroit. The weekend event was sponsored by Les Stanford Chevrolet and has about 250 members. One of the weekend activities was a Corvette-only driving tour of the Milford Proving Grounds. George Haddad, owner of Fabulous Restorations brought his stunning replica of the Owens Corning 1969 Corvette L88 (Stunning L88 Replica, July ’18) from his shop in Fort Lauderdale, Florida. The original Owens Corning Corvette team traces its heritage back to its headquarters in Troy, Michigan. In addition, the team did some testing at the Milford Proving Grounds. With the Milford Proving Grounds driving tour on the schedule, George invited John Heinricy to drive his L88 replica on the tour, and John accepted his invitation.

The Milford Proving Grounds opened in September 1924 and has been in continuous operation ever since. The facility covers 4,000 acres in two counties and is the largest automotive test facility in the world. It is home to over 5,300 employees and operates 24/7/365. This giant property has 174 buildings, many miles of roadway and the famous 67-acre Vehicle Dynamic Test Area (VDTA) known as “Black Lake.” It is also home to the Milford Road Course (MRC) that is used extensively for suspension evaluation. Security is always tight at Milford because of the “secret” vehicles undergoing testing.

Our NCRS tour began in the parking lot of Bakers of Milford restaurant. Only Corvettes were allowed to pass through the entrance (Gate 104) of the proving ground complex. Our rental Chevy Cruze did not qualify, so we had to hunt for a ride. Fortunately, Tom Dingman (Detroit NCRS Judging Chairman) invited us to take photos from his beautiful Nassau Blue ’65 L78 (396/425) coupe. Tom is a Corvette hobbyist who lives in Michigan and restored this car himself.

Close to 50 Corvettes of every generation left Bakers under police escort to make the 3.6-mile drive to the proving grounds. Tom tucked in behind the stunning L88 replica and the throaty rumble of two big-block engines entertained us. The group met inside the administration building for a security briefing and the signing of waivers. At the end of our driving tour we had arranged, in advance, to do a private photo shoot with John driving the L88 replica on the 3-mile Milford straightaway and the MRC. It was a dreary, rainy day, but Heinricy and Dingman kept both cars in the correct positions for our photos. After our tour we caravanned back to Bakers and returned the L88 to its trailer. We said our goodbyes and everyone, including Heinricy, had big smiles on their faces after touring this historic place. Vette

1969 C3 Corvette Milford Proving Ground L88 001 2/23

Close to 50 Corvettes met at the Bakers at Milford restaurant where we began our 3.6-mile drive the Milford Proving Grounds. Tom Dingman owns the No. 74 Nassau Blue ’65 Corvette coupe parked in front of Bakers. This was our camera car.

1969 C3 Corvette Milford Proving Ground L88 002 3/23

John Heinricy joined GM in 1970 and retired as Director of GM High Performance Vehicles Operations in 2008

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Heinricy drove for the Morrison Motorsports team in the ’80s and ‘90s. Here he is competing at the 1995 24 Hours of Daytona in a ZR-1. It was painted like the soon to be released ’96 Corvette Grand Sport. John managed the development of the production C4 Grand Sport program.

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This ZR-1 prototype (EX 5669) broke the 24-hour average speed record at 175.885 mph; the prior record had stood since 1940. The following people helped set this record (from left): Dave McLellan, Corvette Chief Engineer (ret); Tommy Morrison, owner Morrison Motorsports; Ralph Kramer, Director of GM Public Relations (ret); John Heinricy, driver; and Jim Minneker, driver. This car resides in the National Corvette Museum (www.corvettemuseum.org).

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The ’96 Grand Sport continues to be one of the most valuable Corvettes from the C4 generation. Only 1,000 were built, and Heinricy owns VIN#0001.

Photography by Walt Thurn

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