John Hennessey says the Bugatti Chiron prototype that the French automaker used to blast through the 300 mph (482 km/h) barrier could have as much as 2,000 hp on tap.

Bugatti itself claims that the top speed prototype pumps out 1,578 hp from its quad-turbocharged 8.0-liter W16 engine. That would give it a 100 hp bump over the Chiron Sport. Hennessey is not convinced, and speaking with Top Gear, said Bugatti is probably being conservative.

“I’m really intrigued by how much horsepower Bugatti’s engine was really making on the run. To run 40+ mph faster than the Chiron Sport that TG tested on the same track would take a lot more than a 100bhp bump, lowered suspension and some rear aero adjustments,” Hennessey said. “We’re guessing that their one-off Chiron was pushing closer to 2,000bhp. Saying that, I am most impressed by Michelin. How that team was able to validate a tire capable of 300+ mph is great. We knew that their tires were capable of this and Bugatti helped them prove it.”

While Bugatti may have been the first automaker to exceed 300 mph, the fact that it didn’t do so in both directions means the 304.77 mph (490.47 km/h) has not been verified by Guinness and Hennessey believes the race for the true production car top speed record is still on.

Also Read: Hennessey Congratulates Bugatti On Top Speed Record, Says It Wants To Hit 310.6 MPH (500 KM/H)

“I believe that the race to a production series 300mph (with a two-way average speed) road car is still on and that this title remains up for grabs,” he said. “Our goal is still to build the fastest and most exciting road car with the best power-to-weight ratio. F5 will be at least 450kg lighter than the Chiron, and will have more power than they are claiming. We can beat it and have a couple of highways in the USA where we think we would have enough room to hit our absolute top speed, but we would prefer to do this in Texas if possible.”

The Hennessey Venom GT once held a claim to the title of the world’s fastest production car after hitting 270.4 mph (435 km/h) in 2014, but that speed wasn’t verified by Guinness as it wasn’t the average from two runs and the Texas tuner received some flak for it. Hennessey plans on doing everything by the book with the Venom F5.

“We congratulate our friends at Bugatti on reaching an amazing speed. But as a Bugatti executive once told me, ‘next time be sure to run in both directions’,” Hennessey said.