NHRA Saftey Requirements

[Maverick9110E]

Well as we all love our speed, when we take it to the tracks, depending on how fast you run you may need certain saftey features. Here are the NHRA Rules to help when building the power into your ride. Courtesey of Hot Rod mag.

14.99

To prevent radiator overflow from leaking onto the track, NHRA requires an overflow can of at least one pint in volume. This can be as simple as routing a radiator overflow tube into a windshield washer reservoir.

All cars should also be equipped with a proper battery hold-down, even when the battery is in the stock location. Factory stock hold-downs are acceptable in this case. Otherwise, bolts of 3/8-inch diameter must be used to retain the battery. Lug nuts are another area of concern, especially with aftermarket wheels. NHRA recommends all cars be equipped with open-ended lug nuts to allow the inspector to verify the length of thread engagement.

Obviously, all lug nuts and studs must be in place. For slower cars, this isn’t a critical point, especially when using O.E.M. wheels. But with faster cars and aftermarket wheels, the concern is that the lug nut engage the threads of the stud for a distance at least equal to the diameter of the stud. Inquire at your local track as to what the tech inspector will accept.


Since fire is an ever-present threat, NHRA specifies no more than a total of 12 inches of rubber fuel line in the fuel delivery system. This includes the rubber line between the pickup and an external fuel pump and also between the fuel pump and carburetor. In the case of an accident, rubber line is susceptible to damage that could cause a fire. Investing in either steel hard line or braided-steel fuel line is both wise and far safer than using rubber fuel line. Some type of reverse lockout for aftermarket shifters is also required for all cars.

13.99

NHRA requires a DOT, SNELL or SFI helmet for any car quicker than 14.00. There are a number of different specs so you should check with your local tech inspector.

For cars that run e.t.’s between 12.00 and 13.99, all of the above requirements apply along with the addition of a driveshaft loop. A new-for-’95 rule exempts cars running 13.00 and slower when equipped with street tires. Since traction is the key to going quick, this places more strain on the driveshaft. To prevent the driveshaft from breaking at the front U-joint area and perhaps coming into the interior of the car, or digging into the track and pole-vaulting the car, NHRA mandates that a steel loop be placed just behind the front U-joint of the driveshaft. A universal driveshaft loop is available from Lakewood that bolts to the floorpan. A rollbar is required in this e.t. bracket only if the car is a convertible.

11.99

By the time a car is capable of running between 11.00 and 11.99 seconds in the quarter-mile, safety requirements are especially important. Up until this point, factory seatbelts are acceptable, but in the 11-second-and-quicker time zone you need a quality safety harness. The minimum requirement is a 3-inch-wide, five-point harness meeting SFI spec 16.1. The 1995 National Hot Rod Association Rulebook outlines the proper way to mount the shoulder harness and belts.


An NHRA-legal rollbar is also required in the category. Recent rule changes have reconfigured what NHRA classifies as a rollbar. The classic four-point bar is no longer acceptable. The new standard is mild-steel tubing of at least .120-inch wall thickness (most chassis companies, like Art Morrison, use .134-inch wall tubing) that includes a forward-running side bar from the main hoop past the driver’s shoulder. This bar is only required on the driver’s side, but most systems include both sides for a six-point rollbar.

An SFI-approved scattershield is also necessary in this e.t. category. NHRA requires the scattershield to have an SFI aluminum-foil sticker. According to Red Roberts of McLeod Industries, older bellhousings can be certified by sending the scattershield and block plate to the original manufacturer. The company will inspect the housing and if it passes, it will receive an SFI 6-1 certification. Most SFI certifications are good for five years. Contact your manufacturer if you’re not sure.

The clutch and flywheel must also be SFI certified. The main consideration in this area is to avoid using a cast-iron flywheel. According to Roberts, sometime in the mid-’70s most of the new car companies began using nodular iron flywheels that are much safer. Most, if not all, current high-performance aluminum and steel flywheels are safe when used in conjunction with an approved scattershield, but the rules state that the pressure plate and flywheel need an SFI certification number. Roberts says the best plan is to record all your SFI numbers in a logbook. This makes it easier for the tech inspector and it shows the inspector that you understand the importance of the inspection process. This e.t. level also requires steel valve stems in all wheels, along with arm restraints for open-cockpit cars like roadsters.

10.99

Cars running between 10.00 and 10.99 need all the above-mentioned safety equipment, plus driver’s protective clothing, aftermarket axles and an SFI-approved harmonic balancer. The driver needs to have at least a single-layer, SFI-approved jacket such as those sold by companies like Diest, Simpson, RJR and others, as well as long pants and approved driver’s gloves.


The aftermarket axle requirement also extends to installing a C-clip eliminator kit in any rearend that uses a C-clip to retain the rear axle, such as the GM 10- and 12-bolts and the Ford 8.8-inch rearends. While the current NHRA axle rule does not include an SFI spec for axles, experienced axle manufacturers such as Summers Brothers, Mark Williams, Strange and others offer axles intended for this kind of abuse.

Harmonic balancers first became a subject of concern on blown cars that placed enormous loads on the balancer driving the supercharger. Now, any car running quicker than 10.99 needs an SFI-approved harmonic balancer to be legal. Companies like Vibratech, TCI, BHJ and others can supply the necessary legal part.

A new NHRA safety rule change for 1995 states that cars running between 10.00 and 10.99 must have a rollcage unless the car has an unaltered firewall, floorpan and body (except for wheeltubs). This means if you have a street car with a stock floorpan and firewall but have tubbed it for bigger tires, all you need is a five-point rollbar until the car runs quicker than 10.00. Of course, a rollcage is perfectly acceptable if you wish to install one.

9.99
Now we’re into the really quick cars, those running from 9.00 to 9.99 seconds in the quarter. These cars are blazingly fast and capable of speeds approaching 150 mph. Significant improvements must be made to the car in order to step into the 9-second zone. Foremost among these is a rollcage. The cage must be constructed of mild-steel tubing at least 15/8 inch in diameter, with .120-inch wall thickness. It can also be chrome-moly tubing of .083-inch wall thickness with a total of eight attachment points. These eight points refer to the placement of the cage surrounding the driver, including the two rear support bars. NHRA does not require bars that run forward to the front suspension, although many cage designs include them. All cars running 9.99 or quicker must have the cage certified by NHRA and have the NHRA certification sticker attached to the cage.

Attached to the cage is a window net to keep the driver’s arms inside the car. The driver must also wear a neck collar and fireproof clothing meeting an SFI spec. Additional requirements include an NHRA competition license, an external electrical shutoff and a flexplate/automatic transmission shield. If your car can run over 150 mph in the quarter, as many of these cars do, then NHRA also requires a parachute to help slow the car down. Now that we’ve primed the pump, your best bet is to obtain a 1995 NHRA Rulebook for $10 and carefully read the E.T. Bracket General Regulations section. The Rulebook specifies exactly what will be required depending upon your car’s e.t. capability. Drag racing with fast street cars is tons of fun. It’s even better when you do it safely.

[Lisa]

Good info, thanks!