Update: Thursday's event at the Park Jefferson Speedway is rained out.

JEFFERSON, S.D. -- Two events are on tap for this week for the Iron Man Challenge featuring USRA Karl Chevrolet Stock Cars and USRA Karl Performance Parts B-Mods racing in conjunction with the USMTS Modifieds.

The grind for the Iron Man Challenge title resumes this Thursday, June 23, at the Park Jefferson Speedway in Jefferson, S.D., and then rolls into Rock Rapids, Iowa, on Friday night, June 24, at the Rapid Speedway.

Both events are first-time stops for the tough-as-nails tour, and both events will also feature USRA Hobby Stocks battling for national points in the American Racer USRA Weekly Racing Series.

Gates open at 5 p.m., hot laps start at 7 and races begin at 7:30 both days.

The Park Jefferson Speedway is a 4/10-mile semi-banked clay oval located just north of Sioux City off of I-29 at exit 4, then 2 blocks east to SR 105, then 1.8 miles north. For more information, call 515-832-7944.

The Rapid Speedway is a 3/8-mile semi-banked dirt oval  located 0.5 mile east of US 75 on SR 9, then 0.5 mile south on S. Tama St. (at the Lyons County Fairgrounds). For more information, call the track hotline at 712-472-3742.

USRA Karl Chevrolet Stock Cars will be racing for $700 to win and $125 to start the main event both days while B-Mods battle for $500 to win and $75 to start.

Defending Iron Man Challenge Stock Car champion Nathan Wood of Sigourney, Iowa, holds the points lead with four races in the books, but is just 15 points ahead of Independence, Iowa’s Justin Temeyer.

In the B-Mods, Matt Lettow of Roland, Iowa, remains atop the points with defending American Racer USRA Weekly Racing Series B-Mod National Champion Brandon Hare of Elma is second.

IRON MAN CHALLENGE POINTS

USRA Karl Chevrolet Stock Cars:
1. 52 Nathan Wood, Sigourney, Iowa ... 331
2. 56t Justin Temeyer, Independence, Iowa ... 316
3. 2j Steve Jackson, Polk City, Iowa ... 286
4. 66 Jeff Joldersma, McClelland, Iowa ... 268
5. 27T Tory Reicks, Waucoma, Iowa ... 226
6. 14 Todd Staley, Webster City, Iowa ... 222
7. 18 Tom Schmitt, Independence, Iowa ... 219
8. 01u Chris Ulrich, Kiron, Iowa ... 213
9. 33 Kevin Donlan, Decorah, Iowa ... 191
10. R31 Ryan Leeman, Roland, Iowa ... 179

USRA Karl Performance Parts B-Mods:
1. 21L Matt Lettow, Roland, Iowa ... 275
2. 56H Brandon Hare, Elma, Iowa ... 187
3. 64 Brandon Leeman, Roland, Iowa ... 182
4. 76x Troy Hovey, Decorah, Iowa ... 176
5. 7t Jared Timmerman, Norwalk, Iowa ... 173
6. 14 Brian Schrage, Cresco, Iowa ... 165
7. 4ord Bob Sutherland, Blairsburg, Iowa ... 161
8. 28 Parker Hale, Grand Meadow, Minn. ... 150
9. 91 Tyler Johnson, Sioux Falls, S.D. ... 140
10. 7 Carter VanDenBerg, Oskaloosa, Iowa ... 136

2011 IRON MAN CHALLENGE SCHEDULE

Sat Apr 2 ... I-35 Speedway, Winston, Mo.
Thu May 26 ... Highway 3 Raceway, Allison, Iowa
Sat May 28 ... Deer Creek Speedway, Spring Valley, Minn. (Stock Cars only)
Sun Jun 12 ... Nobles County Speedway, Worthington, Minn.
Mon Jun 13 ... Mineral City Speedway, Fort Dodge, Iowa
Thu Jun 23 … Park Jefferson Speedway, Jefferson, S.D.
Fri Jun 24 ... Rapid Speedway, Rock Rapids, Iowa
Mon Jul 11 ... Southern Iowa Speedway, Oskaloosa, Iowa
Tue Jul 12 ... Southern Iowa Speedway, Oskaloosa, Iowa
Thu Jul 14 ... Chateau Raceway, Lansing, Minn. (B-Mods only)
Wed Jul 20 ... Southern Iowa Speedway, Oskaloosa, Iowa
Thu Jul 21 … Bloomfield Speedway, Bloomfield, Iowa
Sat Aug 20 ... Upper Iowa Speedway, Decorah, Iowa
Sun Aug 21 ... Nobles County Speedway, Worthington, Minn.
Thu Aug 25 ... I-35 Speedway, Winston, Mo.
Sat Aug 27 ... Hamilton County Speedway, Webster City, Iowa
Thu Sep 1 ... Highway 3 Raceway, Allison, Iowa

Seventeen dates at twelve dirt ovals comprise the 2011 schedule for the second season of the Iron Man Challenge. Points for both classes will be awarded based on a driver’s 10 best nights.

The points fund for the Stock Cars carries a $2,000 top prize with the tenth-place finisher earning $200. In the B-Mod class, the points champion will earn $700 with tenth-place taking home $100.

Licensed USRA drivers in both classes will also earn national points in the USRA Weekly Racing Series. To earn points and be eligible for points funds, drivers must possess a valid USRA Competitor License, utilize the American Racer KK704 racing tire on all four wheels and compete in at least ten events.

There will be an entry fee of $25 for Stock Cars and $15 for B-Mods at each event.

To learn more about the USRA, visit www.usraracing.com or call 515-832-6000. You can also like us on Facebook, join us on MySpace or follow us on Twitter.

= = = = = = = = = = = = = = =

USRA OFFICIAL SPONSORS: American Racer Racing Tires, Awesome Race Suits, Intercomp, Karl Chevrolet, Karl Performance Parts, KEVKO Oil Pans & Components, NITROQUEST, RACEceiver, RHS – Racing Head Service, Western Flyer HotMods.

USRA PARTICIPATING SPONSORS: Boubin Tire & Automotive, BRODIX Cylinder Heads, DAY Motor Sports, DirtKnights.com, SpeedNet Direct.

USRA CONTINGENCY SPONSORS: COMP Cams, Dirthead.com, Eibach Springs, Forty9Designs.com, Genesis Shocks, Hooker Custom Harness, KSE Racing Products, Marsh Racing Wheels, New Vision Graphics, PBM Performance Products, Real Racing Wheels, Wehrs Machine & Racing Products.