The following Stock/Super Stock horsepower changes were released December 19, 2012 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, 2013. 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 bbachelder@nhra.com.
Stock Horsepower Changes
Complete for 2nd half rating period of 2012
Engine OEM NHRA New
Make CID HP HP HP Years Affected
Chev 402 375 405 411 1970 Nova
GM 346 305 349 357 99-02 Camaro, Firebird manual trans
GM 350 275-285 335 340 93-98 Camaro, Firebird manual trans
Chev 346 345 340 345 00-04 Corvette
Chev 427 425 425 435 2012 Copo Camaro
Chev 262 170 188 191 1996 S-10
Mopar 392 375 426 429 2010 Drag Pak
Mopar 512 450 467 478 2011 Drag Pak
Dodge 153 150 171 175 89-91 Daytona
Mopar 360 275 310 317 09-10 Drag Pak
Ford 428 375 406 416 2010 Cobra Jet
Ford 302 500 500 507 2013 Cobra Jet
Ford 330 450 481 492 2012 Cobra Jet
Ford 330 425 466 477 2008 Cobra Jet
Pont 400 340 335 340 1968 Firebird
Pont 400 325 325 330 1967 Firebird
Super Stock Horsepower Changes
Complete for 2nd half rating period of 2012
Engine OEM NHRA NEW
Make CID HP HP HP Years Affected
AMC 290 225 210 213 66-69 AMX
Cadi 350 170 195 200 78-79 GT only
GM 350 275-300 291 295 92-98 GT only
GM 305 215 255 259 85-86 Camaro, Firebird
Chev 305 220 238 244 1989 GT only
GM 305 210-215 246 252 85-86 Camaro, Firebird
Mopar 345 305 305 312 09-10 Drag Pak
Ford 351 330 330 335 1971 GT only
Ford 330 425 425 430 2008 GT only
Ford 427 425 476 482 1964 Fairlane manual trans
Ford 330 425 445 456 2008 Cobra Jet
Ford 428 375 380 389 2010 Cobra Jet
Super Stock Index Changes
Class Old Index New Index
SS/DX 9.05 8.95
SS/GM 10.35 10.30
