Monza Mirage

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Origins of the 1977 Chevrolet Monza Mirage


by Stacy Scharch


GM debuted a newer RWD H-body hatchback platform for 1975 models, an adaptation of the older Vega body style but, slightly longer. Chevrolet's entry was this HR07 Chevrolet Monza 2+2 sport coupe. Originally designed for a Wankel motor that was never produced, Chevrolet offered two engines for 1975 models.











2.3L 2-bbl Four


Std. (1)



4.3L (262 cid)

2-bbl V-8


Avail. (1)




 (1) California Emission Equipment required in California

*80 HP with California Emission Equipment

Dealer promotional commercial for Monza Mirage

The 1975 Chevrolet 1HR07 Monza 2+2 Hatchback debut


GM's first car project designed using CAD technology was the H platform Chevrolet Monza. They needed an answer to the 1973 gas crisis and other entries of foreign subcompacts and Ford's 1974 Mustang II,.


The car was originally designed to be powered by GM's new Wankel engine that was under development but later dropped because of reliability and fuel economy issues. Also, expensive royalty payments to the patent holder made the engine platform less appealing. It was essentially a Vega H-body rear wheel drive chassis lengthened by 4 inches for styling and to accommodate enough space for a Chevrolet small-block V8. GM had high hopes for their new EPA driven down-sized sports sedan with good performance potential.


Chevrolet's new 1975 Monza, hit showrooms with three different models; a mid-year introduced notchback coupe and two hatchbacks, the S, and the 2+2. But, sitting next to the hatchbacks that debuted to the press in July 1974, was Chevrolet's full-bore, flared-fender Monza racecar. It was made possible only through the efforts of Vince Piggins, who led Chevrolet's Product Promotion Engineering Department.


The 1977 Chevrolet Monza Mirage


Styling for the new trim package took its queue from the highly successful IMSA Monza GT racecar. It was so visually appealing, it gave rise to the idea of an optional sporty street version. The result was the 1977 Monza Mirage.


In the beginning, GM commissioned Michigan based BORT (British Overseas Racing Team) of Grand Rapids, Michigan to design a special limited edition trim package that could be easily applied over a factory finished Monza body.


Michigan Auto Techniques Corporation (MAT), an aftermarket company, was contracted to manufacture and install the components for the 8,000 or more orders originally anticipated. The body flares and spoilers were manufactured using Reaction Injection Molded (RIM) polyurethane material.


The Monza Mirage package from Michigan Auto Techniques Corporation


The Monza Mirage sport package was ordered through participating Chevrolet dealerships. A 1HR07 Monza 2+2 Hatchback Coupe in Antique White (11L-11U) was specified, and with any available 1977 interior.


Following assembly of a Monza 2+2 hatchback at GM's plant in St. Therese, Quebec. Then it was drop shipped to MAT in Grand Rapids, who installed the special Mirage body panels, decals and stripes. The RIM panels were attached directly to the factory fenders with pop-rivets, similar to installation of vinyl siding on a house, after which, the decals were also applied.


Fourteen separate urethane body parts were mechanically fastened over the factory finish of a new Monza. The front air dam was shipped inside the vehicle for dealer installation to facilitate loading and unloading during transit.


MAT Special Equipment "Ship Through" Receipt

  • Front fenders (2 pc.)

  • Rear fenders (2 pc.)

  • Front spoiler (3 pc.)

  • Rear spoiler (1 pc.)

  • Extrusions and end caps (6 pc.)

  • Decals and striping (17 pc.)

  • Blacked-out headlight and lower front grille openings



Street vs. Racecar





Monza Mirage - MAT ad (2-page)

Monza Mirage - MAT ad (4-page)

Monza Mirage - Specifications

Monza Racecar - photo database

Chevrolet Extras Recommended and other RPO Codes





Body Color Sport Mirrors



Heavy Duty Sport Suspension



5.0-liter 2-bbl V-8 Engine



Sport steering Wheel



BR70-13/C White Lettered Radial Tires



Special Instrumentation



Mirage Sport Appearance Package





View of Firethorn red interior

View of 4-speed manual shift

Some Monza Mirages were produced with the standard 140 CID (2.3L) Overhead Cam two-barrel L-4. The only available V-8 engine for the '77 Monza was a 305 CID (5.0L) 2-bbl, which replaced the 262 CID (4.3L) 2-bbl V-8.


Each Monza Mirage serial number, from Michigan Automotive Techniques Corporation (MAT), was affixed to a self-adhering embossed vinyl "Mirage" plaque located in the interior. Mirage serial numbers were consecutive and recorded along with the VIN at MAT. 


There were approximately 2,400 Monza Mirages turned out by MAT. Additionally, some Mirage packages were assembled at dealerships. The entire sport package was available to the public and could be ordered from dealer parts departments.



End of Trail for H-body RWD


A total 731,504 Monzas were produced in six years. The H-body rear wheel drive Monza, Sunbird, Skyhawk, and Starfire were replaced in the spring of 1981 by GM's new J platform line-up. The J-body (FWD) line-up for 1982 included the 1982 Chevrolet Cavalier, Oldsmobile Firenza, Buick Skyhawk, and Pontiac J2000.


Because the forthcoming J-body cars were to be sold as 1982 models, there was a long production run of 1980 H-body models in order to provide sufficient inventory to carry dealers until the spring of 1981. GM's so called H platform designation was reintroduced in 1986, but as its new full-size front wheel drive line up.


In 2008, there were an estimated (25-30) '77 Monza Mirages in running order.


This is the IMSA GT racecar that inspired the Monza Mirage street version. The racecar was created by Lee Dykstra and Horst Kwech of DeKon Engineering, LTD.  DeKon c/n1005 is driven by Horst Kwech at the IMSA Camel GT, 6 Hours of Mid-Ohio endurance race on August 24, 1975. The car sold to notable racer and friend Allan Moffat later in the year. He fell for the car's ease of handling and top speed of 202 mph at Daytona.



Al Unser piloting a Monza DeKon c/n1003 tube-frame racecar at IMSA Camel GT - 250 mile Daytona Finale on November 30, 1975.



Al Holbert owned and drove this championship winning Monza, chassis no. 1008 was built by DeKon Engineering. Photo taken at the Daytona Finale 250-mile IMSA Camel GT race Nov. 28, 1976.



The red, white and blue DeKon cars, specifically the No. 1 car campaigned by Mike Keyser, made an impact on the public. Think about it, American cars racing against domineering foreign cars on American soil during the American bicentennial year, and then actually winning.

Mirage's Inspiration... IMSA silhouette racecars


The car was interesting enough to convince John Bishop of the International Motor Sports Association (IMSA) to initiate an entirely new racing class to allow "silhouette" construction techniques, in which the profile of the car stayed relatively the same, but covered a purpose-built, tube-frame chassis. Racers were anxious to get their hands on something that would give Porsche a run for their money in the burgeoning IMSA Camel GT Challenge Series and its new class AAGT (All-American Grand Touring). 


The General Motors Corporation contracted with DeKon Engineering, LTD of Libertyville, IL to design and build the first of several Monza bodied race cars. DeKon was the partnership of automotive engineer Lee Dykstra, formerly with Kar Kraft Engineering, and Horst Kwech a racecar builder and SCCA Trans-Am championship driver. The company name was a concatenation of 'De' for design and 'Kon' for construction and used the first letter of the owners last names.


In late 1974, DeKon received their first Monza body, a stripped chassis, produced at GM's St. Therese assembly plant in Canada and began building chassis #1001. The new race chassis used structural tubing to build a space-frame that was clad with an OEM Monza tub. Only the original doors, roof, and rear deck lid remained. The front end of the factory chassis was cut off and fitted with specially designed serviceable framework for the engine and new fiberglass body panels. The original fenders were replaced with wide fiberglass flares. An aerodynamic front air dam and rear wrap-around spoiler was added. A custom designed coil-over suspension was bolted to the frame along with large diameter air-cooled brakes and Lockheed 8-piston calipers. Big beefy slicks were mounted on lightweight BBS wheels at all four corners. Extensive testing took place at GM Technical Center in Warren, MI to analyze the racecar's suspension and handling characteristics.


A 5.7 liter Chevrolet small-block V8 engine that developed as much as 600 hp was selected and strategically positioned within the new frame. It was pulled back to the firewall and offset a few inches from center to counter-balance the driver's weight. This gave the DeKon Monza a near 50/50 weight distribution. The car weighed approximately 2,400 pounds when complete.


Chevrolet's showroom stock Monza had a MSRP of just under $4,000. Then DeKon transformed into a lightning quick silhouette racecar for around $37,000. They built fourteen Monza racers, although not all of their chassis have an identification plate. There were also many other privateers who built Monza racecars for IMSA and Trans-Am racing. DeKon became the most successful and well known of the HO7 racecar builders.



Monza Motorsports


Monza's participation in the IMSA Camel GT Challenge Series new AAGT class allowed them to compete with the best GT cars in the world. The 1975 season was launched with the new cars that would compete with the dominating Porsche Carreras. A very liberal set of rules allowed some body panels to be retained - the windshield, the rear window and the roof. Everything else was built from scratch.


Al Holbert saw the potential of the Monza. By the end of the 1975 season, he ordered a brand new car prepared by Dekon Engineering. Chassis #1008 would be used starting for the 1976 season. Holbert won the IMSA Camel GT Champion in '76 and '77, beating Hans Stuck, Brian Redman, and Peter Gregg.  Al's successful 1977 campaign he captured another IMSA crown. Unfortunately, it would be the last title for an American car.


The Porsche 935s were becoming unbeatable right from the beginning of the 1978 season when IMSA allowed the German cars (two) turbochargers. But, the Dekon Monza left its footprint on the IMSA Camel GT series. They were quite unbeatable in 1976-1977. Chevrolet Monzas disappeared from the IMSA circuit after 1986, and descended to the ranks of the SCCA Trans-Am pro series and its amateur club racing.


Today, Monzas are still roaring around the track at vintage races on the west coast, out east, and down south. The cars are still very exciting for race fans to watch. A ground-up replica of Monza DeKon #1006 was recently built in France and appears at the Le Mans Classic. The asking price for a race-ready Monza is said to be more than $250.000.






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