Remember when Hennessey Performance revealed the utterly bonkers VelociRaptor 6x6 a year ago and announced plans to build it?

Well, the company wasn’t kidding as it rolled out the first example in November at the 2017 SEMA show. And now customer examples are being built at Hennessey's headquarters in Sealy, Texas, and just 50 are planned for the 2018 model year. Depending on demand, the company could build a further 50 examples for sale outside the United States.

Based on the F-150 Raptor SuperCrew, the VelociRaptor 6x6 is 4-door performance pickup with locking rear axles, upgraded Fox suspension, custom 20-inch wheels, off-road tires, flared wheel arches, a sport bar and LED lights.

Yes, it’s a big, hulking truck, and yes it’s entirely worthy of competing against equally nutty 6-wheelers from across the pond such as the Mercedes-AMG G63 6x6 and Kahn Design Flying Huntsman 110 WB 6x6.

The starting price for the 2018 model year is $349,000, which includes the cost of the donor Raptor plus a tune of the 3.5-liter twin-turbocharged V-6 so that it delivers 605 horsepower and 622 pound-feet of torque, up from the stock 450 hp and 510 lb-ft rating. The setup is good for 0-60 mph acceleration of 4.9 seconds, which is amazing for a truck of this size. Hennessey says weight is up about 700 pounds over stock.

The upgrade includes custom turbochargers, a high-flow exhaust system, a bigger intercooler, and full ECU tuning. For buyers with really deep pockets, Hennessey also offers an upgraded Brembo brake package, larger wheels, and interior upgrades for an additional $22,000.

2017 Hennessey VelociRaptor 6x6

2017 Hennessey VelociRaptor 6x6

Buyers also receive a 3-year/36,000-mile warranty.

So what's it actually like to drive? We haven’t spent any time behind the wheel but according to Hennessey the VelociRaptor 6x6 feels very much like a stock Raptor, though you’re definitely aware that there’s something extra out back.

Interestingly, Hennessey CEO and founder John Hennessey says he never intended to build custom pickups. The journey started when a customer asked for a twin-turbo upgrade for a 2010 Raptor. Once news of the truck got out, helped along by an appearance on "Top Gear USA", the demand skyrocketed and Hennessey happily obliged. The company has since built more than a 1,000 custom Raptors.