440 ex vs YFZ 450
I've seen 400exs(well, a 465 and some 490s) go 4.9 and the 465 went 48 a couple times. A stock yfz will go around 5.6 or 5.7 from what I've seen. I've ran some 5.8s on a mild 440ex(pipe and maybe a cam) with the front end in the air through third gear.