Sport Mod Differentials

Dirt modified racing delivers high-horsepower, adrenaline-fueled action, learn more about them and their racing classes

Explore dirt stock car racing’s key terms, classes, rules, parts, and tips for success in this ultimate guide for new competitors.

Comparing open diff vs limited slip vs locker differentials. Learn how each works, pros and cons, and which is best for your build.

A short article explaining the main differences between open and limited slip differentials.

A brief overview of the steps Speedway Motors takes to ensure you get a quality differential.

Learn what gear oils do for your differential and how to choose the best gear lubricant for your application's needs

Devyn Peterson is an Auto Tech in the Speedway Motors Customer Experience center. He's also a racer, starting out in karts when he was just 5 years old. He moved up to a Modified when he was 13 and hasn't looked back!

Learn a few tips on how to properly mount Modified bodies and some products that will help get your race car body fabrication job done!

What is the difference between 305, 360, and 410 sprint cars? From engines and horsepower to speed, cost, and racing series, both winged and wingless – we the racing experts from Speedway Motors break it down.

These days, muscle cars aren't just for straight line blasts down the dragstrip. Here's a primer on some of the trick hardware that's available to make your muscle car into a corner carving Pro Touring car that can do it all.