Heim got around Gibbs on Lap 25 of 41 to take the lead for the first and only time and held off a late charge from Austin Hill to win Friday’s Clean Harbors 100.
Heim entered the race trailing Gibbs by eight points and now trails by two as the series moves next to Michigan on Aug. 20.
The win is Heim’s fifth of the 2021 season for his No. 20 Venturini Motorsports team.
“Everything that we could possibly bring to the race track we did today,” Heim, 19, said. “This Venturini Motorsports has battled back from a lot this season and I’m really proud of them. This Camry was really, really good today.”
Cup Series regular Chase Briscoe led the race but was forced to hit pit road on Lap 24 with suspension issues, handing the race lead over to Gibbs.
After running briefly side-by-side, Heim cleared Gibbs for the lead the very next lap.
The two drivers made contact last week at Winchester (Ind.) Speedway with two laps remaining with Gibbs getting around Heim and holding on for the win.
Asked about racing with Gibbs on Friday for the lead, Heim said, “He was just another car on the race track and I was trying to get the lead. I raced him hard, raced him clean and he did, too.
“I just happened to bring home the win today.”
Gibbs ended up third, Carson Hocevar was fourth and Brandon Jones rounded out the top-five.