The 1987, news leaked out from General Motors (GM) that it was working on a development of the Corvette nicknamed ‘King of Hill’. They key to the new car would be a very powerful engine. Codenamed LT5, GM handed development of the vehicle over to its UK subsidiary, Lotus. The original target set fir the ZR-1 was to create the fastest production car in the world, without sacrificing low speed drive ability or fuel economy. The new engine also had to fit in the engine bay, a task made more tricky because the Corvette engine was offered into the nose from underneath. The upshot was a space between the chassis rails of 27x27in (69×69 cm). The engine capacity had to stay at 5.7 liters, a figure much revered by US Corvette fans. Lotus’s development of the engine centered on sophisticated, but it ended up talking the best part of four years to get the LT5 engine into the production car. Clever features included two fuel injectors for each cylinder and a variable valve timing system, but the engine didn’t quite manage 400 lb/ft of torque, finally setting at 380 bhp. Even so, GM claimed 180 mph (288 km/h) for the ZR-1. GM took the ZR-1’s sheer power very seriously by equipping the car with two ignition keys.
One started the car and allowed it to run at 80 percent of its maximum power using just three valves and one injector per cylinder. The second activated a power key on the centre-console to open up all 32 valves and 16 injectors. According to GM’s boss, ‘Some owners wouldn’t want their spouses or sons in change of the car’s full potential’
