One of the World of Outlaws rule updates issued this week in advance of the 2025 season may as well be called the Paul Silva – Kyle Larson Rule.

Chapter 3, Section 1, Q.

Q. Steel and stainless-steel headers will be allowed. Titanium headers will not be permitted. Elbows on the exhaust after the header tube enters the collector, will not be allowed. All exhaust must exit toward the rear of the car. Heat deflecting measures may be used to protect parts at the rear of the car, at the discretion of World of Outlaws Sprint Car Series officials.

This clearly targets a trend started by Silva, the mastermind crew chief behind the success sustained by Larson in a Sprint Car and one that was started to be replicated in various circles in both winged and non-wing racing.

Coincidentally or not, Larson started racing with turned up headers right after he and Silva failed to qualify into the Kings Royal main event and right before going on a successful stretch into the summer that included their third victory in the Knoxville Nationals.

There has been a lot of conjecture about how the modification generates downforce or prevents overheating of the suspension or tires or maybe it’s all a mind game to the rest of the competition. Regardless, it’s not allowed in World of Outlaws competition moving forward.

What else?

Chapter 3, Section 1, F, d.

d. Once the draw has commenced, a team may not enter a backup car in order to manipulate the car count to gain an advantage in the qualifying order.

This is to prevent a team from manufacturing a better qualifying spot. Once an entry list reaches 38 cars, World of Outlaws splits qualifying into two groups instead of one at 37 or less. There has been numerous instances of a team, recognizing that they are qualifying late once the track slows down, will enter a backup car just get reach 38 and two flights.

It’s still possible that a team can enter a 38th car but it will require a headcount prior to the qualifying draw.

Chapter 3, Section 2, C.

C. A fuel cell with bladder and foam will be the only type of fuel cells allowed. The fuel cell shell must be of one-piece construction of cross-link polyethylene plastic. Alterations and modifications will not be permitted. It is highly recommended 6 mounting points be used for the fuel cell. All fuel cell mounting bolts must be safety wired.

This is a response to all the crashes over the past 15 months, where fuel cells have become increasingly dislodged from cars. Fixing this is a priority for the entire industry.

Chapter 3, Section 8, A, c.

a.        A removable wicker bill, maximum height of 1.500 inch, may be mounted on the rear edge of the top wing center foil. Wicker bill must be 90 degrees to the top of the center foil. Built-in wicker bills or gurney lips will not be permitted. The maximum dimension of the wicker bill may change periodically at the discretion of World of Outlaws Officials. Any such changes will be issued in writing prior to the event in which the change will be made.

The increased maximum height of the wicker bill comes after continued discussions with our partners following the National Sprint Car Council meeting at PRI and determining it’s in the best interest of the Sprint Car industry. This will put most of the 410 Winged Sprint Car series across the country on the same wicker bill.

Last year, World of Outlaws went from a 2” wicker bill on top wings to 1” and now it’s going to 1.5”. This follows what High Limit Racing did earlier in the winter as well.

Drivers felt like they were spinning their wheels earlier in a run, not getting the traction they needed, and actually making it harder to pass. The move away from the 2” wicker was about trying to clean up dirty air.

There was a lot of conviction that the issues faced by drivers and teams is more about parity than it is cleaning up dirty air.

In other changes:

Chapter 3, Section 11, D. d.

c.        Seats must be used as supplied and installed following instructions provided by the seat manufacturer. When spacers are used, they must conform to the seat and to the seat mounting tubing of the chassis. It is highly recommended the back mounting spacers are 2” or less in length.

Additionally, fire suppression systems, which are mandatory to compete with the World of Outlaws, that are two years old must be recertified to meet the SFI specification. Contact the manufacturers such as Lifeline and SPA for recertification.

Chapter 3, Section 5, G.

G. Axles 

a.         Only front axles made of magnetic steel will be permitted. Approved front axle dimensions are:

i)            2 1/4” diameter x .120” material thickness
ii)         2 3/8” diameter x .095” material thickness
iii)      2 1/2” diameter x .095” material thickness

b.       Ultra-light rear axles are not recommended for 2025 and will not be allowed in 2026. After Jan. 1, 2026, the maximum inside diameter of the rear axle will be 1.8750.”