The following Stock/Super Stock horsepower changes were released December 16, 2011 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, 2012. 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 2011
Engine OEM NHRA New
Make CID HP HP HP Years Affected
Chev 327 250 245 251 64-65 Big car
GM 346 305/310 373 382 99-02 Camaro/Firebird
Dodge 146 220/230 241 245 2004 Neon
Dodge 225 110 142 144 77-81 Diplomat
Dodge 345 305 401 411 09-10 Drag Pak
Dodge 360 275 299 303 09-10 Drag Pak
Dodge 370 385 385 390 09-10 Drag Pak manual only
Dodge 512 450 456 467 2011 Drag Pak
Ford 302 215 210 213 94-95 Mustang
Ford 352 285 295 302 2010 Cobra Jet
Ford 428 375 388 397 2010 Cobra Jet
Super Stock Horsepower Changes
Complete for 2nd half rating period of 2011
Engine OEM NHRA
Make CID HP HP New HP Years Affected
Chev 265 200 207 211 95-96 GT only
Chev 350 247 276 283 1991 GT only
Ford 330 425 425 435 2008 Cobra Jet
Ford 330 435 435 441 2010 Cobra Jet
Ford 330 500 529 536 2010 Cobra Jet
Ford 330 500 576 589 2010 Cobra Jet
Ford 352 285 285 289 2010 Cobra Jet
Ford 428 375 375 380 2010 Cobra Jet
Pont 305 145/155 250 256 79-84 GT only
Pont 428 390 330 335 1968 GT only
Super Stock Index Changes
Class Old Index New Index
SS/DS 10.90 10.85
