Heck, I know they lose a lot of bottome end. I know they're more hassle then they're worth on the street, I've seen a well tuned single four beat em up on the dyno, and I'm still looking for a pair of 390's to put on a Windsor stroker!!!!! The eyeball appeal and the kewl factor has got to be worth something. Besides, I run a 5 speed and can twist the snot out of it and make it work on the street, too!!!!