Rarlyl8 hit it right on the head.
Along with the useful info that Rarlyl8 has already said. Keep in mind The hot side size (number, for a kkk) will determine lag or lack of it. When dealing with a kkk that hot side number should be no bigger than an 11 for the street.
2004 3500 Dodge
2006 Haulmark Toter
2005 three car stacker