Nobody needs to go 280 or 300 mph. Hardly anybody has the space available (or the fortitude required) to drive those speeds. But everybody wants to know which car is fastest. The custodians of such info at Guinness will tell you that in 2017 the 277.9-mph Koenigsegg Agera RS snatched that record from 2010’s 267.9-mph Bugatti Veyron 16.4 Super Sport. Well, on Saturday, October 10, the famed publication’s record monitors gathered alongside a closed, seven-mile section of Highway 160 near Pahrump, Nevada to observe a new record in the making, set by U.K. pro racer Oliver Webb at the wheel of a supercar hailing from Richland, Washington, the SSC Tuatara. The new speed? A staggering 315.7 mph!

The SSC team spent a week acclimating Webb to the car, starting out on a 3,800-foot runway achieving speeds of up to 204 and 205 mph; then decamped three hours away to a longer, 7,000-foot runway, where Webb managed to hit 270 mph, at which point the whole team felt comfortable attempting the run. SSC North America founder Jarod Shelby (no relation to Carroll), who has done nearly all of the test driving prior to bringing Webb on for the record, rode shotgun for some of these runs and was humbled by Webb’s F1-driver comfort level regarding proximity to the end of the runway before initiating braking. “I’m thinking, ‘when in the world is he going to get on the brakes?’ He braked way later than I would have.”

Then on the morning of the big run, following a few modest 100-mph passes to warm the drivetrain, with crosswinds just slightly under the 10-mph limit the team had set for itself, the team instrumented the car and sent Webb off for his first run.

That run achieved 285 mph—comfortably above the official 278-mph record bogey. On his return he hit 301.07 mph—nearing the unofficial 301-mph Hennessey Venom F5 and 304-mph Bugatti Chiron Super Sport claims, but neither of those times were officially witnessed by Guinness as an average of runs in opposite directions within close timing to account for wind. The crosswind was picking up, but Webb agreed to do one more run and one more only. That pass, replacing the 285-mph one, managed to hit 331.15 mph, for an official 316.11-mph (508.0-kph) top speed. And Webb is said to have acknowledged that the car had more top speed in it, but that was as fast as he was comfortable going.

When we covered the SSC Tuatara back in 2011, the plan was to upsize the 6.4-liter twin-turbo V-8 engine it designed for the SSC Ultimate Aero, the Tuatara’s predecessor, to 7.0 liters. But founder Jarod Shelby wanted to fit a flat-plane crank to the engine, and there’s just no getting an engine that big to live in a production car capable of achieving 300-plus mph while still remaining drivable around town or at a track. So in 2013 the 7.0-liter engine was abandoned in favor of a 5.9-liter version with a meticulously balanced crank and exotic engine mounts filled with a proprietary gel.

The engine is rated at 1,750 horsepower and 1,280 lb-ft of torque when running on E85 fuel (as it was for the speed-record run—top speed is projected to fall to 295 mph running on 91-octane pump gasoline, which drops the power rating to 1,350 horsepower). The engine spins to a lofty 8,800 rpm and requires an impressive 11 different heat exchangers, including two whoppers for the dedicated air-to-water intercooler system, which is said to be capable of dropping boosted air temperatures by 160 to 200 degrees. Four more radiators cool the engine, two cool the gearbox, and one each take care of the engine oil, power steering, and air conditioning. The gearbox, by the way, is a seven-speed auto-clutch manual by CIMA/Automac Engineering, which has its basis in a helicopter transmission.

The roster of aero tricks is remarkably unremarkable. Naturally there’s a full-body belly pan incorporating venturis that direct air out a rear diffuser while creating downforce, air curtains for the front wheels, small fins ahead of the front wheels, and modest little rear winglets. The drag coefficient is 0.279, and the front/rear aero-weight balance remains at a constant 37/63 percent from 150 to 312 mph. Air flows so efficiently over former Pininfarina designer Jason Castriota’s bodywork that with the side windows open at 200 mph, barely any air comes in unless you stick a hand out to scoop some. Italy’s Potio Engineering assisted in designing the elaborate ductwork that conducts air efficiently through all those radiators and coolers, drawing on their its extensive F1 simulation experience.

While achieving speed records grabs great headlines, Shelby is keen to point out that the Tuatara (named for a lizard indigenous to New Zealand that purportedly has the fastest molecular evolution of any living animal) is first and foremost a daily-drivable car designed to tear up a road circuit. The steering system provides some evidence of this assertion—it uses electricity to vary the ratio, but the assistance is purely hydraulic and it gets its own oil cooler, which clearly could only be useful on a handling circuit, not on a seven-mile arrow-straight closed highway. And a big driver of the flat-plane crank design was its unique sound signature. Shelby realizes cars like this are emotional purchases, and they need a visceral sound to connect with buyers. He wanted something less howling than a Ferrari, but also nothing like an American muscle car. The company worked with muffler experts to tune out some low-frequencies and ended up with a unique engine note.

After showings at Pebble Beach in 2019 and at the Philadelphia Motor Show in February 2020, the first customer car has been delivered and there are plans to build 99 more at the company’s purpose-built facility in Washington. We very much look forward to assessing Shelby’s claims of the Tuatara’s track prowess. We will not be probing its top speed.