Hennessey's Corvette ZR1 makes 1,139 hp at the wheels.

The McLaren 720S is one of the meanest supercars around, but the model can't complete against Hennessey's tuned Chevrolet Corvette ZR1. In this video, the Texas-based company shows what its 'Vette can do. 

In stock form, the Corvette ZR1 makes 755 horsepower (563 kilowatts) and 715 foot-pounds (969 newton-meters) of torque, but Hennessey works some magic to push the output from its HPE1200 package to 1,200 horsepower (895 kilowatts) and 1066 pound-feet (1,445 Newton-meters) of torque. A dyno video shows the setup making 1,139 hp (849 hp) and 994 lb-ft (1,348 Nm) at the wheels.

Comparatively, the 720S arrives here with a stock 710 hp (529 kW) and 568 lb-ft (770 Nm). With a 490-hp (365-kW) deficit, there's not much that the British supercar can do to keep up with this Corvette.

These two are racing from a roll. As soon as they get on the throttle, the Corvette quickly pulls away and leaves the McLaren in the dust. 

With the winner of these races a foregone conclusion, just sit back and enjoy the noise. Hennessey gives the Corvette HPE1200 a ported version of the factory supercharger that whines like a banshee. There's also a high-flow throttle body, upgraded pulleys, new camshafts, ported cylinder heats, improved valve springs, and long-tube stainless steel headers. The eight-speed automatic gearbox also receives improvements to handle the extra power.

Hennessey charges $59,950 for the HPE1200 package. Clients also need a ZR1 to donate for the modifications.

The company offers tuning packages for the McLaren 720S, too. The top HPE1000 includes parts like upgraded turbos, stainless steel headers, custom engine management, and an improved transmission. It would be intriguing to see how it performs against the ZR1 in this clip.