Tom Wilson
June 1, 2007
Photos By: E. John Thawley III
Nearly anything goes in NASA's American Iron Extreme, but so far, the car of choice is the Mustang. Paul Brown leads the way in his new AIX racer sporting his Tiger Racing carbon bodywork and ex-World Challenge 351 small-block power. Patrick Lindsey's American Iron Fox was a last-minute addition to AIX at Mid-Ohio-he finished Second in the AIX championship round. Look for this car in American Iron in 2007. Just to prove anything goes, Paul Faessler's first-generation Mustang came out of NASA's now-obsolete AI Vintage class to nearly win the AIX championship. He was taking the race to Rocco when a broken valve stem put a tire down, ending his drive. Built by Paul's Automotive Engineering in Cincinnati, this coupe will be a force in AIX.

Horse Sense: Under-tired by design, AIX cars inherently provide the stage for a superior driver to shine. Similar to Super Street Outlaw drag cars, AIX racers would benefit immensely from a true racing chassis and huge racing slicks. It would also ruin the class.

All of us in the 5.0&SF magazine family are power junkies. When it comes to racing where the chassis is king, horsepower still sings the siren's call. So there's little doubt why we're looking at American Iron Extreme this month. It's the most powerful, wildest outlet for Mustang enthusiasts with a bent for corners and four-digit power ratings. Where else can you race a Mustang with no limits on displacement and power adders are welcome?

That's the sort of thing we've come to expect from the National Auto Sport Association [(510) 232-6272;]. Approaching sanctioning as a business rather than a club, NASA's philosophy is to embrace the aftermarket and its ready-made supply of go-fast parts. The same stuff you're buying for your street Mustang is the same stuff NASA expects you to run at its races.

You can buy a lot of stuff by the time you reach AIX, which is the pinnacle of a three-level class structure. To start is NASA's Camaro-Mustang Challenge and CMC2 for S197 Mustangs and LS1-powered Chevys. Here, the powertrains remain stock-all the way down to the crimped factory headers-with simple spring, sway bar, and shock chassis improvements. The class is well subscribed, and the cars are excellent teaching tools as they're traction-limited with smaller tires and torquey engines.

Paul Brown was the fastest at Mid-Ohio and could've easily won the AIX championship, but a last-minute engine change meant he started the race three laps after the green flag dropped. He unlapped himself once, set the fastest race lap, and finished Sixth. With seven years driving and prepping Mustangs in the World Challenge, Paul is likely the most experienced racer in the AIX field.

Next is NASA's most popular Mustang class, American Iron. Here you'll find a larger gaggle of pure-race Mustangs and a few Camaros sporting a spec Toyo tire, modest fender flares, and whatever engine mods work to be within a 9.5 pounds per horsepower limit. NASA uses a chassis dyno to verify the horsepower; in practice you see something with more than 300 hp and cars on both sides of 3,000 pounds. Suspension mods are fairly liberal, and these cars are plenty fast and fun to drive. We've driven several and they're precise, satisfying race cars that'll hold your interest for decades.

When "plenty fast and fun" isn't enough, there's American Iron Extreme. Conceptually, AIX is AI without the power-to-weight limitation. The idea is to limit the expense without limiting the modifications. That it results in road-racing rockets and should soon yield something akin to pod racers doesn't seem to bother anyone.

NASA's ingenious rules are written to be as free as possible, but with a few important choke points. In AIX any transmission is legal, but it must be readily available at no more than $6,000 retail. Any brake, fender flare and nearly any suspension is legal, but the maximum wheel size is 18x11 inches; only DOT-approved tires may be run and traction control isn't allowed. Even though any gasoline-burning piston engine can be run, all power adders are allowed except for nitrous, and displacement is unrestricted. You can see there is only so much grip available and only so much power can be run through a $6,000 transmission on a road course. But it's still a lot.

It's good to be number one, and Ernesto is enjoying his year as AIX champion. The ex-mountain bike racer is in excellent shape for driving these hot, noisy, high-g race cars.

Other noteworthy technicalities are a minimum weight of 2,700 pounds with driver, the floorpan or unibody must remain intact, the firewall may not be relocated, shock towers must remain in place (although they need not be used), and there is a minimum 100-inch wheelbase requirement. A rear wing may be run but is limited in size and setback, and no car older than a '60 is allowed. Neither are foreign cars-this is American Iron Extreme, after all. Fox and SN-95 Mustangs are favored because they're inexpensive, adaptable, and available. Early adopters can run S197 Mustangs, but they're heavier than the earlier cars, which are stiffened with a rollcage. The weight negates the S197's chassis rigidity advantage it enjoys on the street.

For the record, Corvettes aren't allowed as they don't have a back seat, Pintos aren't long enough to qualify, but the new Pontiac GTO is legal. So are old Valiants, Falcons, Camaros, Darts, Mustangs, Novas, and so on. Remember, any engine-turbo 2.3 to Cosworth DFV F1 V-8 to a Keith Black Hemi-can be put in any legal chassis.