Two winners emerged Sunday after two late-race lead changes highlighted the main events for the Industrial Material Surplus Iron Man Challenge event at the I-35 Speedway in Winston, Mo.

Both the USRA Stock Cars and USRA B-Mods will be in action this Sunday, March 25, when the Iron Man Challenge accompanies the USMTS Modifieds to the I-35 Speedway in Winston, Mo., for the Annual Yancy’s Automotive Missouri Meltdown.

Saturday's race at the I-35 Speedway has been moved back one day to Sunday, March 25. The event at the LA Raceway has been postponed until Thursday, April 19.

Officials from the United States Racing Association have released the 2012 schedule for the popular USRA Iron Man Challenge featuring USRA Karl Chevrolet Stock Cars and USRA Karl Performance Parts B-Mods.

The Iron Man Challenge invaded the I-35 Speedway in Winston, Mo., for the second time this season Thursday night with two new winners visiting victory lane at the 3/8-mile dirt oval.

In just eight days, two new champions of the USRA Iron Man Challenge will emerge. With the final four events of the 2011 campaign between now and then, the racing action will be boiling hot as the USRA Karl Chevrolet Stock Car and USRA Karl Performance Parts B-Mod drivers battle it out for this year’s titles.

Six events are in the books for the Iron Man Challenge featuring USRA Karl Chevrolet Stock Cars and USRA Karl Performance Parts B-Mods, with 10 different winners emerging from 11 feature races so far.

The USRA Iron Man Challenge kicked off the 2011 season Saturday night at the I-35 Speedway in Winston, Mo., with the USRA Karl Chevrolet Stock Cars being joined by the USRA Karl Performance Parts B-Mods for the first time.