The Chevrolet experimental Monza Super Spyder II, derived from the Chevrolet Monza 2+2, will be a top attraction of the Chicago Auto Show February 21-29 in McCormick Place.  The car is acknowledged to be among the most aerodynamically efficient designed cars ever produced in America.  An aerodynamic front end with a unique strip-lighting system; special gold-flake custom exterior paint; and a low profile hood with fresh air intake are special features of the above hatchback model.  Other attractions include an exterior mounted digital readout speedometer and a functional, negative-lift, rear air-spoiler mounted horizontally across the rear deck lid for maximum effectiveness.

The pictures on the right were taken by Ken Mahoy at a Chevrolet Vega meet in Green Bay, WI in 2000, and were used with his permission.
Based on the interior, the car used was a 1975 Chevrolet Monza 2+2 but also used the Borg Warner 5-speed that didn't see the light of day until the 1976 model year.  Unfortunately only one of these prototypes was ever produced and it was used on the Auto Show curcuit in 1976.  GM still owns the car and it only sees the light of day every few years or so, most recently at another Cosworth Vega meet in Michigan, 2006.  
Ken also provides the following info on the Stiletto on ...

Prototype Monza 2+2 that was originally developed by Jerry Palmer at the GM Design Center as a "lighting concept", with a Corvettte-looking front nose, rounded-off one-piece rear tail section with a fixed rear spoiler, reminiscent of the GTO Judge, and louvered taillights (like the '66 GTO).  GM lighting engineers developed a long fluorescent tube buried in the car's nose behind a plexiglass shield that provided low-beam illumination for urban night driving, while twin high-powered Cibie driving lights were faired into the underside of the nose for high-speed travel.  Powertrain was the 16-valve Cosworth engine, except with twin (45mm) Weber carbs, and a Borg Warner 5-speed coupled with a 4:10 rear axle.  It was painted a unique "Palomino Platinum Gold" colour.  The hood had very nice visual effects, such as extensive pinstriping and clearance blisters which were intentionally asymetrical to simulate an aircraft fuselage.  One blister was a functional passenger-side air intake, and the driver's side blister housed a digital speedometer.  Under the flaired fenders resided FR60-14 Goodrich Radial T/A's on German BBS lightweight racing wheels (14x7 front, 14x8 rear).  Visually, it was one of the most pleasing Monza prototypes ever built.
Click above and below for larger photos 
Motor Trend, January 1977 - Click on each for full-size page