Stiffen the front, soften the rear. Try to think about how the weight will be transferred to the tires. When you have a stiffer front, and softer rear the weight will be shifted to the rear tires more, and thats where you get your grip. More rear grip = tighter, and so when you take away front end grip, you also get tighter. Hope that makes sense.
If its an oval you will also have to set the truck up for only left hand turns, which could mean a softer right side than the left to get more grip in the turns. A stiffer left rear shock will also help you on entry and exit, where the softer right rear will give you more grip. A softer right front will make it turn more, as will a softer left front, just not as much.
TLR - Spektrum - Pro-Line - Stickit1- Schelle - B-Fast Performance