Hp and E.T. 'S
Well its simple pysics, really. Even the old mopar chassis/engine bibles have the info in them if you bother to read them. It requires a certain amount of horsepower to move a certain weight of car down the 1/4, at a particular MPH. The confusion that i notice, is guys get hung up on trying to compare ET to horsepower, and you cannot do that. HOWEVER, weight and MPH CAN be used to figure horsepower though. As for weather changes, yes, it will effect the MPH, because it will effect the HP your engine is producing at that time of your run.