My truck sags pretty bad in the back end when I hook up my trailer and was looking for a solution. I know nothing about truck suspension, so I'm hoping someone can suggest something for me to try. The truck is a 78'F-150 w/ 400cu. Got alot of pulling power it just sags like a old lady in the back end! Just got an AWDIRECT catalog in and seen a kit for $150 made by Timbren(load boosters). Anyone have any experience with these? Or would you recommend somthin else.