SFI 4.1 transmission shield required at 10.99 and faster
NHRA…
10.99 seconds (6.99 1/8th) or Super Street
SFI 4.1 Transmission Shield, or at 135 mph Locking transmission dipstick tube Aftermarket axles and axle retainers
SFI Harmonic Balancer
Roll Cage with altered floor pans, or 135 mph - Window net required Ignition cut-off on all bikes / snowmobiles that exceed 135 mph
IHRA
TRANSMISSION SHIELD: SFI 4.1 mandatory on all automatic transmissions equipped entries running 10.99 and quicker 1/4 mile or 6.99 and quicker 1/8 mile.
