Sorry for the delay in responding.....I drive a UPS truck and I have had trucks with both drum and disc brakes. The discs stop so much better; thats kind of the reason I wanted to upgrade. I am not planning on changing engines, but my UPS truck goes a little faster than my 6400(which dosen't go anywhere now). Maybe with such a speed diference, I wouldn't need an upgrade after all. What do you experienced guys think?
