Dirt Modified Racing Classes Explained | A-Mod, B-Mod, and E-Mod

The name “modified” comes from the sport’s early days, when racers would strip down and modify old production cars to make them lighter and faster. But that was then—today’s modifieds aren’t like anything you’d see on a showroom floor. They’re purpose-built machines designed from the ground up with one goal in mind: tearing around dirt ovals.

In the hierarchy of dirt track racing classes, modifieds occupy something of a middle ground. They’re more sophisticated and powerful than beginner-level stock cars, but definitely more accessible and affordable than high-dollar, high-tech Late Models. Compared to sprint cars, which are lighter, quicker, and often equipped with large wings for downforce, modifieds are considered more approachable and controllable. It’s those qualities, and many others that we’ll explore here, that help make modifieds a favorite at dirt tracks everywhere.

On the higher end, a new A-Mod roller typically starts at around $40,000 give or take, while a fully built, turnkey car can run anywhere from $65,000 up to $100,000-plus, considering the builder and components included. Besides the upfront cost of the car, there are ongoing expenses like tires, fuel, maintenance, spare parts, racing safety gear, entry fees, and transportation, all of which can easily add up to several thousand dollars per season.

There may also be some small weight breaks tied to the engine package. For example, under DIRTcar rules, a 358 Modified running the Wegner W-16 engine might be allowed to be a minimum weight of 2,350 pounds. This helps keep things competitive by offering a more cost-effective engine option within the class. Some tracks make their own adjustments, with spec weights as low as 2,300 pounds for the W-16, and even 2,250 pounds in past seasons. These strict weight limits help maintain parity by emphasizing driver skill and chassis setup over who has the lightest car.

The most common classes are A-Modifieds, B-Modifieds, and E-Modifieds, though some regions feature offshoots or use different names. Each class has its own rulebook that dictates engine limits, suspension setups, body style, and fuel type, among other requirements, which help even the playing field by keeping performance levels in check.

We touched on horsepower earlier, where A-Mods typically produce between 600-750 hp. Combine that with a sophisticated chassis setup, and these beasts are a handful that require some serious skill to control. In short, A-Mods are built for experienced racers who understand vehicle dynamics and can pilot these machines across unpredictable surfaces.

They also feature more complex, adjustable suspension components like torsion bars, dual-rate springs, and even independent front suspensions to fine-tune for different track conditions. Other major differences may include high-end, purpose-built racing shocks and a wider, lower body profile than other modified classes. Rules for A-Mods are usually less restrictive, too, which opens the door for innovation and performance, but can also drive-up costs.

A brand-new roller can be picked up for under $30,000, and engines are easier on the wallet, too. Built B-Mod motors can usually be counted on for around 350-500 hp, while crate options like a 602 or 604 help keep competition fair by limiting customization and overall spending.

B-Mods represent a nice, sweet spot for racers with some experience, or skilled beginners working with a decent, but not unlimited budget. The rules call for simpler suspension setups, often a basic leaf spring or coil-over rear, which makes them easier to tune and less expensive to maintain. That cost-conscious approach extends to shocks, tires, and other components. For a lot of drivers, it’s an affordable way to gain valuable seat time and know-how on their way to the A-Mods.

Engines are usually smaller-displacement crate motors or older rebuilt V8s, putting out a manageable 300-450 hp. So, it’s enough to get the adrenaline pumping without being too much to handle. This is an ideal class for someone who’s never raced before or is stepping up from an entry-level class like Hornets or Bandoleros.

The rules are pretty tight, too, with limited suspension tuning and a focus on keeping things uniform. E-Mods also have a distinct look, where they’re often taller and narrower than an A or B-Mod. Here, driver skill, consistency, and basic setup will get you a lot farther than big spending.

Super Modifieds are ultra-light, open-wheel beasts weighing just 1,650-1,850 pounds and running methanol-injected big- or small-block engines that push upwards of 800 hp. With an offset chassis that shifts the engine and driveline left for better traction, plus a massive 20-inch right-rear tire and adjustable top wing generating serious downforce, they can easily hit 130-140 mph, though they’re usually confined to paved ovals.

Pro Modifieds are another high-horsepower class that can often be found running alongside Late Models at tracks across Louisiana, Arkansas, and Texas, among other locales. While they tip the scales at around 2,400 pounds, they differ from A-Mods in chassis construction, suspension, and other key specs.

The most practical place to start is with your budget. Be realistic about what you can afford in terms of a car and the costs of competing for an entire season. An E-Mod is the cheapest option, including more affordable tires and lower engine maintenance costs. A B-Mod’s crate engine is another predictable expense that helps keep spending in check. The open engines found in most A-Mods, however, can quickly become a bottomless pit when you’re chasing horsepower gains. It’s usually best to start in a class where you can be competitive both financially and on track. And that leads us to…

Your experience and skill as a driver should play a major role as well. Jumping right into a 700 hp A-Mod as a rookie isn’t recommended, since you’d be up against well-funded, seasoned veterans from day one. There’s a reason these entry-level, intermediate, and advanced classes exist. Starting in an E-Mod or B-Mod lets you learn car control, develop race strategy, and chassis setup in a more forgiving and supportive environment.

Lastly, pay attention to what’s available in your region. There’s no point in building an E-Mod if every track within a five-hour drive only runs B-Mods. Visit your local dirt ovals, talk to racers in the pits, and see which divisions have full, evenly matched fields. Connect with promoters and check the major sanctioning bodies like the International Motor Contest Association (IMCA), DIRTcar, and United States Racing Association (USRA) to figure out what classes are most common in your area.

To see the best of the best in person, try catching stops on one of the national touring series like the USMTS (United States Modified Touring Series) or even the World of Outlaws CASE Construction Equipment Late Models, which often includes modifieds on the undercard. Or, you could take in one or more of the sport’s marquee events, like the IMCA Speedway Motors Super Nationals at Iowa’s Boone Speedway; the USRA Nationals at Lucas Oil Speedway in Wheatland, MO; the World Short Track Championship at The Dirt Track at Charlotte Motor Speedway in North Carolina; or the DIRTcar Nationals at Volusia Speedway Park in Florida, which always brings out a number of big-name UMP Modified drivers and builders.

If you can’t make it to the track, you can still follow along from home thanks to streaming services like FloRacing and DirtVision, which carry major modified events as well as weekly programs from dirt tracks across the country. You can also stay connected on social media by following your favorite series, tracks, and drivers for the latest schedules, entries, and results.