The United States Auto Club (USAC) makes its long-awaited return to Lime Rock Park on Friday and Saturday (Oct. 17-18) USAC Weekend, featuring Mustang Cup Challenge and Radical Cup North America.

As the excitement builds for the weekend, here are five storylines to keep an eye on:

1. The return of USAC: It’s been a long time, but USAC has played a major role in the history of Lime Rock Park. On Sept. 7, 1958, George Constantine won the USAC First Annual Lime Rock International Open in an Aston Martin, lowering the track record to 1:05.81-seconds in the process. It was the first professional sports car road race in America, sanctioned by the United States Auto Club.

Then on July 25, 1959, Rodger Ward stunned the motorsports world by taking a stunning victory in the first USAC International Formula Libre: Two months after winning the Indianapolis 500, Ward was driving an 11-year-old Kurtis midget owned by Ken Brenn, beating a diverse field including an ex-Juan Fangio Formula One Maserati 250F along with cars from Formula II and international sports car competition. Ward also set the Lime Rock track record with a lap of 1:04.67-seconds.

2. New series launches racing ladder: This spring, Ford launched a ground-breaking entry-level racing platform to bridge the gap between the Ford Racing Driving Experiences and the Mustang Challenge. The Mustang Cup offers a professionally organized, club-level racing environment for novice and hobby racers to develop the fundamentals of organized racing on private USAC-operated race weekends, using the Mustang Dark Horse R. The weekend features three 30-minute practice sessions, two 15-minute qualifying sessions and two 40-minute races. Success at this level opens the door for the Mustang Challenge and beyond, including Mustangs in IMSA’s top-level series for GT4 and GT3 competition.

3. Mustang Madness: The Mustang Cup North America has two championships within the single-make series, the Miles Cup and Parnelli Cup, with each championship holding one qualifying session and one race per event weekend. This format allows two fellow racers to share one car, splitting the cost, track time and fun of a race weekend. Within each championship there are two classes: Dark Horse and Dark Horse Legends.

The Dark Horse class includes all drivers within the championship, while the Dark Horse Legends class is an optional classification for racers 40 years old and older.

Robert Noaker, Devin Anderson, Marcos Vento, Sandy Satullo and Alex Bachoura lead the championship charge. (Full Championship Standings)

4. Radical competition: The Radical Cup North America offers multi-class sports car racing, enabling motorsports enthusiasts the opportunity to experience Daytona or Le Mans-style competition for a fraction of the price. The series features three spec cars: the SR10 XXR, the Le Mans-inspired Radical extreme coupe and the open-cockpit RXC Spyder, all powered by high-performance race-tuned engines in competition for championships around the world.

5. Battle for the title: The Radical Cup North America’s high-horsepower SR10 Platinum class championship will be decided at this weekend’s season finale, in addition to the battles for second and fourth in the final standings in Pro 1340 and in Pro 1500. Wayne Williams leads Louis Schriber in the Platinum by a mere 19 points. With 40 points for a win and 30 points for third, it would be game on if Schriber took top honors in race one and two with another Platinum driver between himself and Williams – in fact, Schriber would be one point ahead going into the final race of the year. Also watch for Group-A/Radical New York driver Steve Jenks, who has come off the back of two race wins in Atlanta, elevating him to third in the standings, just 10 points further back than Schriber. (Full Championship Standings)

Gates open on Friday at 7:00 a.m. with on-track activity starting at 10:00 a.m., featuring practice and qualifying for all series. Saturday brings racings for all classes, starting at 9:00 a.m. (Weekend Schedule) Weekend passes are just $35. Children 12 and under, active military and veterans receive free admission.