There is a lot of talk about the drop in HP ratings in '72. I was under the impression that the reason for the drop was the way they took the readings. I thought before '72 they took the HP from the motor. In 72 the industry standardized and took readings from the rear wheels. Somebody correct me if I got that wrong. JG:Smarty:
The difference is between Gross HP and Net HP. The old way of rating HP is Gross. This is an engine on a dyno with no alternator, PS pump, and an open source of air (no air cleaner). There may be some other differences I am forgetting. Net is HP rating WITH all of those real world accessories, and a real air intake system. etc. It's more legit. Rear wheel HP is not the same as net. All cars are rated net HP, but I am not aware of any that Advertise RWHP, because it's going to look low. You see RWHP a lot these days because it's an easy way to dyno your car. Just drive up onto the chassis dyno, strap the car down and have at it. With a RWHP number, you can closely estimate the engine HP.
