It’s been seven months since Danny Thompson’s goal of achieving a new Land Speed Record for piston-driven vehicles was postponed by a combination of mechanical and natural issues, but his drive for 400mph-plus continues.

Challenger II – the car originally built by Danny’s father, the late Mickey Thompson, in 1968, set aside but never forgotten, and lovingly restored for a new run for the LSR on the Bonneville Salt Flats by his son and his small band of craftsmen – proved it had record pace on Bonneville’s salt last fall. The twin dry block nitro-fueled Hemi V8 powered, all-wheel-drive, 4000hp Challenger II qualified for the AA/Fuel Streamliner record by averaging 419mph during the final mile, but a second run to back up the record was cut short by a clutch failure, and deteriorating weather forced the cancellation of Bonneville’s World Finals, ending LSR attempts for the year. Since then, Thompson has been retooling for another run this summer

“We decided we’re going to run at what they call the “Test and Tune” on July 9 – it’s just a three-mile track, not for records or anything, but we’ve made some significant changes, and we’ll just make one run to test those changes and see where we are.”

The mods include both tweaks to the twin three-speed gearboxes that link the two engines together and counterbalance output, as well as aero, Thompson explains.

“We’ve made changes to the gear ratios, final drive, transmission changes; we made an aerodynamic change, putting an undertray at the back of the car; we’re going to run more nitromethane. They might only be small changes but, typically, you only want to make one change before you’ve gone running and make sure what you did. At a racetrack you can make a change and go out and run a few laps, come in and see whether it did any good, but at Bonneville you just don’t have those options – you might get three laps the whole week! That’s why we want to test them just to make sure I didn’t step on my toe.”

Thompson says the lessons learned from last year’s runs have provided plenty of data toward Challenger II‘s renewed challenge.

“We know through the telemetry where we need to be at each mile-mark to go fast, so we try to take the curve of where we were last year and back it up about 12 seconds and then pick it up on the top end.”

Following July’s test run, Thompson and his small team consisting mostly of volunteers will head for Bonneville’s Speed Week, set for Aug. 8-14. And he plans to drop the hammer from the outset.

“The first run we’re going to be going for it – we’re not going to do a warm-up run or anything like that,” he says. “The problem with Bonneville is the window of opportunity is so narrow that you’ve really gotta make every single run count. To do what we want to do, everything’s gotta be perfect – the car, the engines, the driver and the salt. And the wind can come up or the weather can close in at any time….”

And all that is within the tiny sliver of opportunity provided by the calendar: “You only get six weeks out of the year to go run,” Thompson notes. “The rest of the time you’re preparing, rebuilding engines, working on sponsorship.”

That last continues to be perhaps the biggest challenge facing Challenger II, Thompson admits.

“If I had a business manager he’d probably cut my hands off!” he laughs. “It’s probably been the most frustrating part of the whole project. We’ve had good publicity from CNN, you guys (RACER), Hot Rod magazine, the Orange County (Calif.) Register. We’ve shown this is no longer just Danny’s dream – it’s really happening. But still, finding funding has been tough.”

As a result, Thompson has been forced to carry on much of the prep work himself. “It’s just been me and one other guy since last October. It’s the hardest thing I’ve ever done.”

But the lure of another chance to fulfill a father and his son’s decades-long ambition is as powerful as ever, and summer can’t come fast enough for Thompson.

“Oh man, I can’t wait,” he says. “I’d run tomorrow if I could!”

• To learn more about the Challenger II and watch videos of it in action, visit thompsonlsr.com