its because the 426 hemis dominated nascar and the nhra...stock for stock the 440 might be good enough to be worth not worrying about tuning, but when modding begins, there is nothing quite like the hemi. i am involved with a fairly large race team, bob george racing, and about half of the guys in the team are very very fast, and run 426 hemis...one of them drives the car on the street with a 9 second hemi car.