i was just on nhra's site, and found nothing in the 2006 rule revision page. i was also on another site, and found this , Driver Restraint Systems A quick-release, 3-inch shoulder harness meeting SFI Spec 16.1, including crotch strap, is mandatory in all cars in competition required by the rules to have a roll bar or a roll cage. Driver restraint system must be clearly labeled as meeting SFI Spec 16.1 and be dated by manufacturer. System must be updated at two-year intervals from date of manufacture. All seat belt and shoulder harness installations must be mutually compatible, originally designed to be used with each other, and produced by the same manufacturer. Cars using OEM or OEM type seat may route crotch strap in front of seat instead of through seat. Only those units that release all five attachment points in one motion are permitted. When arm restraints are worn with a restraint system that utilizes a \"latch lever\", a protective cover must be installed to prevent arm restraint from accidentally releasing the latch lever. Protective cover not needed if system uses \"duckbill\" latch hardware. All harness sections must be mounted to the frame, crossmember, or reinforced mounting, and installed to limit driver's body travel both upward and forward. Seat belts may not be wrapped around lower frame rails. Under no circumstances are bolts inserted through belt webbing permitted for mounting. Check manufacturers instructions . hope this might help jim !!