I might be wrong, but I "think" in FAST the appearance is what counts. It is pretty easy to make '72 heads flow like 70/71. Same with the carb and manifold. It is only in the Pure Stock class that the parts are year specific. Anyone that is running under 12.0 has really got some skills, time and money. Even though I know I won't ever be competitive, I think it is the most interesting class of drag racing and brought me back to the track. I admire the guys that are going faster, they would have been freaking heros back in the '70's with a 10 second 340 Duster. I can't think of any stock appearing muscle car (even with headers etc) back then that came anywhere close to that on stock tires. 132 MPH, wow what a ride. It must pull like a freight train.