The following Stock/Super Stock horsepower changes were released June 28, 2016 produced by the Automatic Horsepower Factoring System (AHFS). This is the first of two scheduled horsepower adjustments for this year. All changes are effective June 28, 2016. 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 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.
A minor change was made this year to the method of calculating runs made at altitude tracks. In the past these runs were converted back to sea level as a part of the calculation. After input from racers and an internal review it was determined that the prior method was not as linear or consistent as the new method of just subtracting the run from the altitude corrected index.
Because the process of making Stock and Super Stock horsepower adjustments involves collecting and performing calculations on large amounts of data, it is possible to make errors. From the completion of the tech. card, to the entry of data into the timing system, to the calculations of the final data itself, errors can be made. We work very hard to minimize those errors, but they still sometimes occur. Usually when a mistake has been made one of our racers quickly points it out to us and we make the correction. Please feel free to contact Pat Cvengros via email at: pcvengros@nhra.com. regarding any questions or concerns about horsepower adjustments.
Stock Horsepower Changes
Complete for 1st half rating period of 2016
Engine OEM NHRA New
Make CID HP HP HP Years Affected
AMC 258 114 148 150 1977 Pacer
Chev 327 275 274 278 66-68 Nova
Chev 350 350 350 355 13-15 COPO
Chev 396 390 414 420 13-15 COPO
Chev 427 425 456 467 12-13 COPO
Chev 427 450 450 461 14-15 COPO
Chry 146 180 204 209 2004 PT Cruiser
Mopar 426 425 415 421 1964 Fury
Dodge 512 450 511 518 2011 Drag Pak
Ford 330 425 497 504 2010 Cobra Jet
Ford 330 450 542 549 2012 Cobra Jet
Super Stock Horsepower Changes
Complete for 1st half rating period of 2016
Engine OEM NHRA
Make CID HP HP New HP Years Affected
Chev 350 530 530 542 14-15 COPO
GM 350 245 275 279 90-92 SS/GT FWD
Chev 350 260 283 287 94-97 SS/GT RWD
Dodge 512 450 467 473 2011 Drag Pak
Ford 302 525 544 557 2014 Cobra Jet
Ford 330 425 505 517 2008 Cobra Jet
Ford 330 435 477 488 2010 Cobra Jet
Ford 351 285 329 334 1971 SS/GT FWD
Ford 428 355 350 355 1969 SS/GT RWD
