The NHRA Technical Department has announced additional rule amendments for the 2021 NHRA Factory Stock Showdown Season. These rule amendments can be found below and on www.nhraracer.com under rules/NHRA rulebook/2021 rulebook amendments.

DESIGNATIONS

Designation: FSS

Reserved for 2008 and newer Chevrolet COPO, Dodge Drag Pak, and Ford Cobra Jet with the following factory production engine of the same make. Year of engine optional. Only those engines and/or bodies listed in this section are eligible for the Factory Stock Showdown.

Minimum weight for all pre-2019 Chevrolet COPO and Ford Cobra Jet combinations 3,450 lbs. except for all Ford Cobra Jet combinations with 2.3L Eaton superchargers 3,275 lbs.

Minimum weight for the 2015 Drag Pak combination 3,500 lbs.

Minimum weight for all 2019 and 2020 Chevrolet COPO, 2021 Drag Pak and 2019 Ford Cobra Jet combinations 3,575 lbs.

Maximum weight on all combinations 3,600 lbs.

Note: NHRA may make adjustments to (minimum weights, supercharger pulley ratios, etc.) at any time to control performance and maintain parity within the category.

Permitted Combinations:

All previously approved Factory Stock Showdown bodies are eligible to be used with the approved engine combinations listed below. Engine must be same make as body.

2017-2018 Camaro COPO 350

•        590 HP Supercharged 2.9L Whipple

2019 Camaro COPO 350

•        630 HP Supercharged 2.65L Magnuson

•        Upper supercharger pulley size: (3.250) inches

•        Supercharger rear jack shaft cog pulley 32 teeth

•        Supercharger rear cog pulley 34 teeth

2020 Camaro COPO 350

•        630 HP Supercharged 2.65L Magnuson

•        Upper supercharger pulley size (3.250) inches

•        Supercharger rear jack shaft cog pulley 32 teeth

•        Supercharger rear cog pulley 34 teeth

2015 Challenger Drag Pak 354

•        540 HP Supercharged 2.9L Whipple

•        Upper supercharger pulley size: (3.000) inches

2021 Challenger Drag Pak 354

•        630 HP Supercharged 3.0L Whipple

•        Upper supercharger pulley size (3.500) inches

•        Lower engine pulley (7.530) inches

2010 Mustang Cobra Jet 330

•        435 HP Supercharged 2.3L Eaton

2012 Mustang Cobra Jet 330

•        450 HP Supercharged 2.3L Eaton

2016 Mustang Cobra Jet 302

•        575 HP Supercharged 2.9L Whipple

2019 Mustang Cobra Jet 327

•        610 HP Supercharged 3.0L Whipple

•        Upper supercharger pulley size: (3.750) (3.625) inches

•        Lower engine pulley 6.938 inches

2019 Mustang Cobra Jet 351

•        570 HP Supercharged 2.9L Whipple

Upper supercharger pulley size: (3.500) inches