The following Stock/Super Stock horsepower changes were released December 18, 2020 produced by the Automatic Horsepower Factoring System (AHFS). This is the scheduled horsepower adjustment for this year. All changes are effective January 1, 2021. 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

Rating period of 2020

As of 12.18.2020

 

Engine                     OEM           NHRA       New

Make           CID      HP             HP            HP            Years Affected

 

GM               305       140 & 145  180           183           76-77 Nova

 

GM               305       155 & 165  262           268           1987 Camaro

 

Chev            350       170             269           273           1977 Nova

 

Chev            350       175             283           287           1973 Nova

 

Chev            350       190             281           285           1981 Corvette

 

Chev            350       350             394           403           13-15 COPO

 

Chev            376       365             383           392           2015 Camaro

 

Chry             318       165             230           236           81-82 Imperial

 

Dodge          370       340             385           394           09-10 Challenger

 

Ford             140       145             171           175           1984 Thunderbird

 

Ford             281       235             282           286           2010 Cobra Jet

 

Ford             302       122 & 137  137            141           1977 Mustang

 

Ford             302       140             145           149           1979 Fairmont

 

Ford             302       215             213           216           94-95 Mustang

 

Ford             315       585             585           593           2019 Cobra Jet

 

Ford             330       450             562           570           2012 Cobra Jet

 

Ford             330       510             522           534           2012 Cobra Jet

 

Olds              305       150             229           232          1984 Cutlass

 

 

 

 

 

 

Super Stock Horsepower Changes

Rating period of 2020

As of 12.18.2020

 

 

Engine                     OEM           NHRA      

Make           CID      HP             HP            New HP   Years Affected

 

Chev            396       390             390           395           13-15 COPO

 

Chev            427       470             486           493           16-20 COPO

 

GM               305       190-230      240           243           88-92 GT RWD

 

GM               305       185-190      238           244           1987 GT FWD

 

GM               305       185-190      243           247           1987 GT FWD

 

GM               350       210-225      290           294           1987 GT RWD

 

GM               350       210-225      300           307           1987 GT FWD

 

GM               350       260             293           300           94-97 GT RWD

 

Dodge          354       530             530           537           2015 Drag Pak

 

Ford             289       210             200           203           1964 GT RWD

 

Ford             330       435             451           462           2010 GT RWD

 

Ford             428       335             354           362           68-70 Mustang

 

Pont             350       170/200      250           256           1974 Ventura