The following Stock/Super Stock horsepower changes were released December 20, 2019 produced by the Automatic Horsepower Factoring System (AHFS). This is the second of two scheduled horsepower adjustments for this year. All changes are effective January 1, 2020. 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 national 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.
Any comments, thoughts, or requests must be sent in writing to: National Hot Rod Association; Technical Department; attn: AHFS; P.O. Box 5555, Glendora, CA 91740; or e-mail, AHFS@nhra.com or pcvengros@nhra.com
Stock Horsepower Changes
Complete for 2nd half rating period of 2019
Engine OEM NHRA New
Make CID HP HP HP Years Affected
Chev 262 170 199 202 1996 S-10
Chev 305 190 237 240 1987 Camaro
Pont 301 210 220 223 1980 Firebird
Super Stock Horsepower Changes
Complete for 2nd half rating period of 2019
Engine OEM NHRA
Make CID HP HP New HP Years Affected
Chev 305 185-190 240 243 1987 GT RWD
Dodge 345 305 320 328 09-10 Drag Pak
Ford 289 210 230 233 1964 Comet
Pont 350 200 250 256 1974 GT RWD
