2004 NASCAR Nextel Cup Series (Start Your Engines!)

The 2004 NASCAR Nextel Cup Series was the 56th season of professional stock car racing in the United States and the 33rd modern-era Cup series season.

This was the first year for the new series sponsorship. Mobile phone provider Nextel assumed sponsorship of the NASCAR championship series from cigarette brand Winston. Winston was the title sponsor of the Cup Series for 33 seasons, from 1971 to 2003. Nextel would become only the second title sponsor in Cup Series history. This was also the first year for Sunoco as it replaced Unocal 76 Brand as the official fuel of NASCAR. Sunoco would become only the second gas company to be NASCAR's official fuel since Unocal had been the official fuel since the sport's inception in 1948.

The season was also marked by tragedy. On October 24, a charter airplane owned by Hendrick Motorsports crashed at Bull Mountain in the Blue Ridge Mountains of Virginia, near Martinsville Speedway. Ten people aboard the plane died, including Randy Dorton, Hendrick's chief engine builder.

2004 was the first season without Pontiac (though a few Pontiacs without factory support ran several early-season races, and Kennedy Racing ran the entire season without factory support). It was also the last season without Clint Bowyer until 2021 and the same time before Denny Hamlin joins NASCAR as a driver (he ran the last 7 races in 2005 before joining full-time in 2006), as well as the first season without Dale Earnhardt since 1974.

Technical changes
For 2004, Dodge wanted to run the newly-reintroduced Charger. However, the car wouldn't begin production until April 2005, and therefore wouldn't be eligible under NASCAR's homologation rules. Dodge instead chose to run a different nose on the existing Intrepid body, mainly taking inspiration from the noses Penske ran in 2003. To this day, the exact identity of this car is still being hotly debated.

For one, Dodge didn't give it a specific model name, using the vague term "Dodge R/T". Dodge dealerships and NASCAR, meanwhile, referred to it as the Dodge Intrepid. Tim Johnson, driver of the #80 at Pacific Coast Racing, took one look at the car, and identified it as a Dodge Stratus. For 2004, Pacific Coast Racing ran the cars with Stratus lettering; by the Coca-Cola 600, Penske and Evernham had also begun putting Stratus lettering on their cars.

Aside from Dodge, Chevy and Ford made no changes to the Monte Carlo and Taurus, respectively.