[Andrew Hill]

Straight from the rule book, "The power-to-weight factor is the shipping weight of the vehicle divided by the advertised, or when applicable, the factored horsepower for the OEM-assembly-line cylinder heads. NHRA-accepted aftermarket cylinder heads carry a horsepower penalty that is calculated to the weight of the vehicle and does not change the class of the vehicle."

I'm not sure when this verbiage was added, but it's in the 2017 and 2018 rule books.

Edit: just realized this quote was already posted on the last page, oops.