The Spyder name was used by GM back in the days of the Corvair, but it was a trim package and had nothing to do with open top motoring like you might expect. The Monza was another attempt by GM to reinvent the subcompact and was essentially a sportier looking version of the H-body Vega.
The Monza was originally intended to be the recipient of GM's Wankel rotary engine, but bean counters and reasonable people agreed that questionable performance, so-so fuel economy, and abysmal quality wasn't in the best interest of anybody...so they ended up shoving a V8 into the front of the small 2+2. Normally this would be a win-win-win proposition, but it was 1979 and smog requirements had reduce carburetor throat diameters to that of roughly a cockatiel's pyloric valve.
This '79 Monza would have been equipped with a 305 cubic inch V8 (the red headed step sister of the 350 V8) that was rated at 130 horsepower or 40 more than the base 2.5 liter inline-4. One can only assume that the power density of a 3 year old on a tricycle generates acceleration like a balloon powered slot car...but what is going on with the red-on-pink interior?
See another 3500 dollar wonder? firstname.lastname@example.org