Lap Belts NHRA Tech Inspection

It really depends on how quick/fast you run. And, it's been my experience that how stringently things are enforced varies from track to track, and promoter to promoter, and sometimes month to month! And it will depend if you are NHRA Class racing, or just doing some casual Friday nite bracket racing.... generally speaking, you'll be OK with basic seat belts unless you're running 11.49 or quicker... and really if you are going quicker than 11.49, you should have good belts anyway.
Here are the rules from the 2018 NHRA rulebook. Sections 4A, 4, 10., and 21, 10.5. Hope this helps!

4A DRIVER RESTRAINT SYSTEM
Seat belt mandatory in all cars. Driver restraint system meeting SFI Spec 16.1 mandatory in any car running 11.49 (*7.35) or
quicker, in convertibles running 13.49 (*8.25) or quicker, and all dune-buggy-type vehicles running 12.00 (*7.50) or slower.
SFI 16.1 restraint system, when required, includes crotch strap and must be updated at two-year intervals from date of
manufacture. See General Regulations 10:5, 10:11.

10:5 DRIVER RESTRAINT SYSTEMS
A quick-release driver restraint system meeting SFI Spec 16.1 or SFI Spec 16.5 is mandatory in all cars in competition
required by the rules to have a roll bar or a roll cage. (Permitted in all other classes.) Driver restraint system must be clearly
labeled as meeting SFI Spec 16.1 or SFI Spec 16.5 and be dated by manufacturer. SFI 16.1 or 16.5 3-inch-wide shoulder
harness straps folded over and sewn to be 2 inches wide by the original manufacturer in order to fit into head and neck restraint
lips/channels are acceptable. See Class Requirements for Section 21, page 44 General Regulations additional requirements for Top Fuel and Funny Car. SFI Spec 16.1 or 16.5 Y-type belts prohibited. (In cases where the class does not require an SFI 16.1 or 16.5 driver restraint system,
the two-year recertification does not apply.)
System must be updated at two-year intervals from date of manufacture. All seat-belt and shoulder harness hardware must be originally designed to be used with each other and produced by the same manufacturer. For harness installation, see illustration. Cars using OEM or OEM-type seat may route crotch strap in front of seat instead of through seat; otherwise, install according to manufacturer’s instructions. Mandatory that units must release
all attachment points (five, six or seven, if applicable) in one action. 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 required if system utilizes “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 framerails. Under no circumstances are bolts inserted through belt webbing
permitted for mounting.

Also, some info on basic roll bars...
4A ROLL BAR
Roll bar mandatory in all cars (including T-tops) running 11.00 (*7.00) to 11.49 (*7.35), in convertibles running 11.00 (*7.00) to
13.49 (*8.25), and in all dune-buggy-type vehicles running 12.00 (*7.50) seconds and slower. Permitted in all cars.
See General Regulations 4:10, 10:6.

HELMET
For all 10.00 to 13.99 closed-bodied cars, either an open face or a full-face Snell M2010, M2015, SA2010, SA2015,
SFI 31.1/2010 or 31.1/2015 helmet with or without a shield is mandatory.