My personal experience with the ch4b is a lot better than the performer on a 440 and now on my 496.I can't fit an rpm under the hood of my C body.I have ran the performer,ch4b,and the street dominator.Yes the sd outperforms them both but I like the low end and the smoother idle of a dual plane intake on my mild 496 in a heavy car.The ch4b is a lot stronger from the mid range up than a performer.It has no problems spinning my 496 to 6k and will eagerly go past it if I don't lift.Is the rpm better?Probably so but it won't work for me.Only way I am cutting the hood is for a tunnel ram.