When in doubt go to NHRA and consult the rule book in racing 101
WINDSHIELD, WINDOWS
Altereds, dragsters: Optional. Windscreen mandatory. See General Regulations 7:7, 7:8.
Stock-bodied vehicles: Mandatory, must be in good condition and free from cracks. May be replaced with shatterproof material, 1/8-inch-minimum thickness. OEM windshield may not be cut for scoops, carb, etc. Windshield/window tint must meet the applicable state requirements. Windows must be closed during races, need not be operable. Decals permitted on rear quarter and rear window only. See General Regulations 7:8. Regulations 6:2.
WINDOW NET
A ribbon-type or SFI 27.1 mesh-type window net is mandatory for any full-bodied car running 7.50 (*4.50) to 9.99 (*6.39) or if vehicle runs 135 mph or faster. See General Regulations 6:3.