The following Stock/Super Stock horsepower changes were released December 12, 2023 produced by the Automatic Horsepower Factoring System (AHFS). This is the scheduled horsepower adjustment for this year. All changes are effective January 1, 2024. 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

 

 

 

Stock Horsepower Changes

 

Engine                  OEM         NHRA      New

Make          CID     HP            HP          HP          Years Affected

 

Chev           302      350           350         355         22-23

 

Chev           305      155-180     244         248         80-84

 

Chev           305      150-155     262         266         85-86

 

GM              305      175           248         252         83-87

 

Chev           327      250           245         249         1965

 

Chev           327      300           265         271         63-65

 

Chev           350      250           224         232         1969

 

Chev           350      300           300         307         1969

 

Chev           350      350           403         413         13-15

 

Chev           350      600           614         622         19-23

 

Chev           409      450           461         467         16-17

 

Chev           427      470           481         492         16-23

 

Dodge         370      340           404         410         09-10

 

Ford            302      140           156         158         1979

 

Ford            302      210           215         218         1985

 

Ford            302      225           215-217   218         87-92

 

Ford            302      500           562         570         2013

 

Ford            330      510           547         554         2012

 

Ford            428      335           383         388         68-70

 

 

Note: See class guide for specific details

 

 

 

Super Stock Horsepower Changes

 

 

Engine                  OEM         NHRA     

Make          CID     HP            HP          New HP   Years Affected

 

GM              305      230           249         253         88-92 GT RWD

 

GM              305      230           253         259         88-92 GT FWD

 

GM              350      210-225     294         301         1987 GT RWD

 

GM              350      225-230     288         292         88-89 GT FWD

 

GM              350      275-300     299         306         92-98 GT FWD

 

Chev           427      425           425         431         12-13

 

Chev           427      430           430         436         14-15

 

Chev           572      500           512         524         22-23

 

Dodge         354      530           550         557         2015

 

Dodge         370      385           385         390         09-10

 

Ford            302      500           536         543         2013

 

Pont            428      390           343         348         1968 GT FWD

 

 

 

Note: See class guide for specific details