Hennessey hits 370km/h in under 20 seconds

Forget 0-100km/h times - the real test of a supercar is how fast it can get to 370km/h, according to US supercar specialists Hennessey.

The Hennessey Venom GT super coupe recorded a 0-370km/h time of 19.96 seconds. To put that speed into perspective, a fully-loaded Boeing 747 would take roughly 40 seconds to reach 300km/h.

The Venom managed 0-200km/h in 7.96 seconds, and 0-300km/h in 13.48 seconds - meaning it gets to 300km/h faster than some small cars take to reach 100km/h.

To produce the GT, Hennessey pulls a 6.2-litre V8 from a Chevrolet Corvette, ditches its supercharger and replaces it with a pair of turbochargers for good measure.

The result is a power output of 895kW and 1565Nm at the rear wheels. The Venom GT weighs in at a little more than 1200 kilograms, or less than most Mazda3-size hatchbacks.

The Hennessey Venom GT is only sold in left-hand-drive. Only 29 examples will be built, and it costs an estimated $US1 million ($A957,000).

Hennessey has tested the car's top speed, and it has so far managed 418km/h - ranking it equal-second fastest in the world alongside the Koenigsegg Agera R.

The company is reportedly working towards challenging the Bugatti Veyron Super Sport's top speed record of 429km/h.