The following Stock/Super Stock horsepower changes were released July 3, 2018 produced by the Automatic Horsepower Factoring System (AHFS). This is the first of two scheduled horsepower adjustments for this year. All changes are effective July 3, 2018. It should be noted that these changes include only results produced by the AHFS, and do not include written letters or requests. Those changes are listed separately.
The AHFS is a program based on actual run data compiled from all available runs at NHRA events. The data-based format provides the ability to calculate average performances for any class and/or engine combination in Stock and Super Stock. The trigger point for the system is 1.00-second or more under the respective index, and must be produced on two different occasions. Engine-combination averages and class averages are then computed and analyzed to determine if a change is warranted. The amount of change is calculated on a stepped percentage basis. Where applicable, adjustments will be effective for the specific car model or body style being evaluated. An automatic adjustment is instituted outside the two-time a year process when a 1.20 and under run is recorded during any NHRA event.
Stock Horsepower Changes
Complete for 1st half rating period of 2018
Engine OEM NHRA New
Make CID HP HP HP Years Affected
Dodge 360 185 279 283 1980 Mirada
Dodge 360 210 265 271 1980 D-150
Ford 302 133 151 153 1976 Mustang
Ford 302 565 573 581 2016 Cobra Jet
Super Stock Horsepower Changes
Complete for 1st half rating period of 2018
Engine OEM NHRA
Make CID HP HP New HP Years Affected
AMC 390 340 423 433 1969 AMX
Chev 396 325-350 379 384 68-69 Camaro
GM 350 240-245 279 283 90-92 GT FWD
Ford 302 500 524 536 2013 Cobra Jet
Ford 302 565 565 573 2016 Cobra Jet
Ford 330 435 540 547 2010 Cobra Jet
Ford 330 435 441 551 2010 GT Cobra Jet
