NHRA Factory Stock Showdown

Factory Stock Showdown (FSS) (in the NHRA), or Pro Stock (in the IHRA) is a class of drag racing designed to showcase the Chevrolet COPO Camaro, Dodge Challenger Drag Pak, and the Ford Mustang Cobra Jet.

FSS continues to be a fan favorite with growing popularity over the last ten years. The popularity of this class of racing is in large part due to the recognizable cars. All three of the types of cars that race in the FSS are standard monocoque chassis cars that are body in white from the factory with all drag racing running gear installed at the factory, using production chassis of the cars on the road.^[1]

While cars competing in FSS are of the same type you see on the road, they do have numerous safety enhancements and rules that are required to be eligible to run in FSS events. Cars are limited to 9" wide tires, must have full safety cages, independent fuel cells, weight limits and other general racing safety requirements. These safety enhancements are in place to allow these cars to run the 1/4 mile at speeds no faster than 7.50 seconds. Since its inception the FSS class has gone faster every year and the NHRA has put restrictions in place to ensure safety and parity between the cars^[2]

Drivers competing in the NHRA Factory Stock Showdown Series earn championships points at each of the NHRA National events at which they compete. The points are accumulated throughout the year, and an annual champion is crowned at the conclusion of the season.^[3]

While the NHRA FSS is the original and preeminent racing series for Factory Stock cars the growth and popularity of FSS racing has been seen through expansion in other series. These include the National Muscle Car Association's (NMCA) Factory Super Car^[4] series and Drag Illustrated's Factory Stock Classic^[5] as examples. In 2026, the International Hot Rod Association eliminated the traditional 500 cubic inch formula for Pro Stock in favour of using the "Pro Stock" moniker for Factory Stock Showdown cars.^[6]