The team improved to be 13th in the points in 1997, but it was obvious the team would not succeed if it only fielded one team. In 1998, Kranefuss announced his team would merge with Penske Racing, and would also change to the #12 with Mobil Oil sponsoring the car. The move turned out to be a success, and Mayfield became the next big star. He won the pole at Texas, and at one point in the season, found himself in the points lead. At the Pocono 500 in June, he won his first Winston Cup series race. Mayfield's breakout year in Winston Cup ended with a 7th-place finish in the points. Mayfield struggled in 1999, as he did not win and dropped 4 spots in the points. In 2000, he won the Pocono 500 and California 500. Midway through the season, Kranefuss sold his share of the team to Penske. Mayfield then suffered a concussion while practicing for the Brickyard 400. He missed two races recuperating from his injury and finished 24th in points. Following 2000, Kranefuss was no longer associated with the Penske No. 12; he fielded a No. 84 Ford for Shawna Robinson in 2001, but only qualified for one of four events attempted, at Michigan.