Holmes would make his indy car debut in the USAC National Championship during 1979 for AMI Racing in the No. 46 Jiffy Mixes/Armstrong Mould Wildcat Mk. 2-Drake Goosen Sparks at the Indianapolis 500. In the race Holmes qualified in 13th place and was the only rookie to qualify, meaning Holmes won the rookie of the year award. Holmes finished the race in seventh place. Holmes drove a second race, the Music 500 Presented by Musicland & Sam Goody at Pocono International Raceway, starting and finishing seventh. Holmes finished 12th in the USAC points, while going unranked towards the rival SCCA/CART PPG World Series due to Indianapolis counting towards the points for drivers competing in their championship.