Sealy, Texas - The Dodge Demon is just about the fastest American-made street legal production car you buy, wielding 618kW from a supercharged 6.2-litre SRT Hemi V8, enough to hit 100km/h from a standing start in 2.5 seconds and blow through the quarter mile (402 metres) in 9.65 seconds at 224km/h.
Which is great for the rest of the United States - and a bit much for those bunny-hugging wusses in California - but not for Texas, where everything just has to be bigger and better. Especially in the sleepy little town of Sealy, just outside Houston, where John Hennessey specialises in making fast cars go faster.
First, the Hemi gets an upgraded throttle body, a more powerful fuel pump and upgraded injectors. The exhaust manifolds are replaced by stainless-steel long tube headers, the inlets by high-flow induction plumbing and the standard 2.7 litre supercharger gets ditched in favour of 4.5-litre monster blower.
Then the dirty fingernail dudes make way for the computer nerds, who re-map the Demon’s ECU to use all that extra breathing capacity - and the result, according to the Hennessey dyno, is an extra 143kW - up to 761kW, backed by 1288Nm of tar-wrinkling torque.