SAN TAN VALLEY, Ariz. — Chaz Baca claimed the first race of the six events on the Arizona Dirt Track Tour in the IMCA modified division on Friday night at Arizona Speedway.

His victory paid $2,000 with payouts at a record high for the fourth year of the series.

A 52-car field drew for heat race starting spots with the winner of each heat moving to the main. With six heats, the top 10 in passing/finishing points joined the heat winners to fill the first eight rows.

Four additional drivers from each of a pair of B mains filled the grid. The top six in points were inverted at the front of the field.

The 25-lap main was a duel between Baca and Ricky Thornton Jr. the entire distance. Thornton led until lap 12 when Baca took the lead with a drive out of turn four. The last 13 laps had a classic duel between the pair with Thornton trying every move known to try and regain the lead.

But Baca made no mistakes and used the top groove to post the win over Thornton and Collen Winebarger.

The 32 IMCA sport mods ran four heats with the winners and top 12 in points moving to the main with the top six in points inverted. An additional eight drivers from the B-main completed the field.

The 20-lap main offered $750 to win and, despite seven yellow flags, excellent racing was displayed among the drivers dicing for a podium finish. Austen Becerra led nine laps before Tyler Soppe was able to lead just a single time around the racy three-eighths-mile dirt track.

Lap 11 became the turning point when Brian Osantowski used the top groove to lead the final 10 laps for the win. Tenth-starting Cody Thompson was second ahead of Soppe as Osantowski took the checkers.

Twenty IMCA stock cars ran two heats with the top 16 in points filling eight rows, again inverting the top six in points.

Ricky Thornton Jr. started in fourth and used the top of turns one and two to lead  by halfway down the backstretch on the opening lap.  A cluster of stock cars battled for second numerous laps before Chanse Hollatz broke away but couldn’t catch Thornton.

The series continues Saturday at Arizona Speedway before moving to Casa Grande’s fairgrounds track.