As the result of runs under the Automatic Horsepower Factoring System (AHFS) 1.20-second under policy at the Mac Tools U.S. Nationals, the following changes have been made.

The horsepower rating for 1986 Chevrolet C-10, entries with the 350 cubic inch engine and a factory rating of 165 currently rated at 171 has been increased by sixteen two horsepower, to 187 horsepower; for Stock Eliminator.

The horsepower rating for 85-86 Ford Thunderbird, Cougar, entries with the 140 cubic inch engine and a factory rating of 145-155 currently rated at 177, has been increased by six horsepower, to 183 horsepower; for Stock Eliminator.

The horsepower rating for 2004 Chrysler PT Cruiser, entries with the 148 cubic inch engine and a factory rating of 180 currently rated at 186, has been increased by eight horsepower, to 194 horsepower; for Stock Eliminator.

NHRA's 2012 Automatic Horsepower Factoring System outlines that any run of 1.20-second or more under the index will receive an immediate index decrease or horsepower increase. These changes are effective Sep. 11, 2012.