On a warm, sunny day in May 1992, a ‘blind’ comparison test was performed by General Motors’ executives on a massive pavement area called Black Lake, deep within the secretive GM Milford Proving Grounds outside of Detroit, Michigan. The conclusions drawn from this test would change the course of history for General Motors Powertrain, its customers and the automobile industry.
At the time, the automotive business was ferociously arguing the merits of building complex, seemingly high tech, dual overhead cam (dohc) internal combustion engines versus building simple, seemingly low tech, pushrod engines. This hands-on comparison by the execs was to put the debate to a seat-of-the-pants experience and allow the leaders of GM to decide the course for the future for GM Powertrain.
The executive leadership of GM would drive pairs of similar appearing vehicles and compare how each vehicle felt—not knowing what engine type was powering the vehicles. Of most interest to readers of this book were two black Corvettes parked at the end of the lineup. One ‘Vette was fitted with a 330 hp, early version of the LT4 Gen II V8 pushrod engine. The other ‘Vette was equipped with the ZR1-spec, Lotus-designed, all-aluminum, dohc engine
full specs . Both vehicles were equipped with automatic transmissions. Both were fully integrated for their specific powerplants to give a real world experience to the executives.
The results surprised even the most ardent supporters of the pushrod architecture. The executives couldn’t get over how one of the ‘Vettes pulled from the moment they pressed on the throttle. The surge. The thrust. The torque.
In contrast, they commented on how the engine in the other ‘Vette seemed to take a moment to ‘wind up’ before pushing them back in the seat. This vehicle required more precision and planning when driving fast, to keep the engine up in the RPM band when the power was needed.
As the day went on, executive after executive came to the same conclusion. After all had tested the vehicles, the hoods were raised. To anyone who has driven or ridden in a 300+ hp small block Chevy V8 engine powered vehicle, it comes as no surprise the Corvette the executives liked was the Gen II pushrod V8-equipped vehicle.
From then on, the course for GMs V8 powertrain was set. The world’s finest pushrod V8 would be created to power the most profitable vehicle’s in the General Motors fleet. This was the birth of the Gen III small block V8.