Until March 25, 2012, the record speed achieved at the Texas Mile was 250.1 miles per hour. Hitting a number like that takes more than a fast car and steady nerves; environmental conditions have to be right, too.

If there’s a head wind or a cross wind, chances are it will slow the car or make it less stable at speed. If the day is warm, the air is less dense and even forced-induction engines will make less horsepower.

When going for a record high speed run, the best time to attempt it is early morning; generally speaking, the air is still and the temperature is as cool as it’s going to get all day. That was the strategy behind Sean Kennedy’s record-setting run at Sunday’s Texas Mile event, and it paid off with a new Texas Mile record speed.

Kennedy piloted a twin-turbo Ford GT, owned by Mark Heidaker, to a top speed of 257.7 miles per hour. Not only did that shatter the existing record, but it beat the team’s closest competition by 4.6 miles per hour.

The record-setting car is purpose-built for high-speed runs. The stock 5.4-liter V-8 has been replaced by an Accufab Racing engine, force-fed by a pair of Precision Turbochargers. Tuning was handled by Shane Tecklenburg of Tuned By Shane T, and Hennessey Performance Engineering (HPE) made the whole package work in harmony.

Kevin Kesterson of HPE said, “I knew when I saw 204 mph come up on the scoreboard at the half mile, that it was on.”  Added Tecklenberg, “We knew the car had it in it. Our task was simply to... figure out a way to apply the power in the right places.”

Unlike the old days of tuning, modern fuel mapping strategies can rely on GPS data to create a power management strategy that takes advantage of traction available at a specific point on the track. In other words, 257.7 is the record speed - for now.

Conditions permitting, the team hopes to break the 260 mph barrier during the next Texas Mile event in late October.