The following Stock/Super Stock horsepower changes were released December 16, 2024 produced by the Automatic Horsepower Factoring System (AHFS). This is the scheduled horsepower adjustment for this year. All changes are effective January 1, 2025. 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 one-time a year process when a 1.30 and under run is recorded during any NHRA event.

         Any comments, thoughts, or requests must be sent to: AHFS@nhra.com or pcvengros@nhra.com

12/16/2024

Stock Horsepower Changes

Engine                  OEM         NHRA      New

Make          CID     HP            HP          HP          Years Affected

Chev           262      140           157         161         1987                                               2.25%

Caprice Auto Trans

Chev           350      350           413         419         2013-2015                      1.25%

Copo Auto Trans

Chev           327      250           249         253         1965                                               1.25%

Chevelle Auto Trans

Chev           350      160/170     273         282         1977-1978                      3.25%

Nova Auto Trans

Chev           396      325           325         336         1967-1969                      3.25%

Camaro Auto Trans

Chev           302      350           355         360         2022-2023                      1.25%

Copo Auto Trans

Chev           327      390           390         395         2020 & 2023           1.25%

Copo Auto Trans

Chev           402      375           390         395         1970                                               1.25%

Nova Manual Trans

Chev           396      375           400         405         1968 & 1969           1.25%

Camaro Manual Trans Rep Heads

Chev           402      375           415         425         1970                                               2.25%

Nova Auto Trans OEM & Rep Heads

Pont            400      180           260         266         1977                                               2.25%

LeMans Auto Trans

Pont            350      160           273         282         1977-1978                      3.25%

Ventura/Phoenix Auto Trans

Pont            400      225/230     275         279         1973-1974                      1.25%

Firebird Auto Trans

Olds            350      160/170     273         282         1977-1978                      3.25%

Omega Auto Trans

Mopar          360      160           289         296         1977                                               2.25%

Aspen – Volare Auto Trans

Dodge         426      460           466         472         2015                                               1.25%

Drag Pac Auto Trans

Ford            351      275           325         330         1972                                               1.25%

Mustang Auto Trans

Ford            428      335           388         397         1968-1970                      2.25%

Mustang – Cougar – Shelby Auto Trans Rep Heads

Ford            302      565           581         595