91 Chevrolet Camaro ZL1 driven by multiple drivers (including Hélio Castroneves in 2025) as part of the team's PROJECT91 program.

Prior to that, he worked for Joe Gibbs Racing as a crew chief for two of their NASCAR Cup Series teams: the No.

Prior to that, Grubb worked for Stewart–Haas Racing from 2009 to 2011 as the crew chief for team co-owner Tony Stewart, winning the Cup Series championship with him in 2011.

Before that, he had another stint at Hendrick Motorsports from 2003 to 2008, starting his career as an engineer and was later the interim crew chief in 2006 for Jimmie Johnson's No.

He graduated with a mechanical engineering degree that year through a co-op program with Volvo Trucks and General Motors.

On September 5, 2008, it was announced that Grubb would be leaving Hendrick Motorsports at the end of the season to join the new Stewart–Haas Racing team to serve as Tony Stewart's crew chief in 2009.

During the 2011 season, Grubb led Stewart from a mediocre pre-chase effort to five chase victories and Stewart's third NASCAR Cup Championship by way of a 5-1 victory tiebreaker over Carl Edwards that NASCAR used in the event of a tie in the points standings at the end of the season.

On July 29, 2014, Grubb was suspended six races for tampered firewall covers, which could lead to more downforce, during the Brickyard 400.

[9] On November 1, 2017, it was announced that Grubb would be the crew chief for William Byron for the 2018 Monster Energy NASCAR Cup Series season.

[10] On October 10, 2018, Hendrick Motorsports announced that Grubb would return to a technical director position while Knaus takes over crew chief duties for the No.

He would also lead Shane van Gisbergen to his first career Cup Series win in his debut at the Chicago Street Course.

16 in the fall Cup Series race at Las Vegas after the team parted ways with Travis Mack.

1 car driven by Ross Chastain in the 2024 season-finale at Phoenix after Phil Surgen was suspended due to the team being a part of the Chevrolet race manipulation at Martinsville the previous weekend.