Taken right off of the interwebz:
The simplest and cheapest lift for trucks using a coilover is a spacer between the strut and upper mount. The vast majority of level lifts on struts are currently done this way.
The downside is uptravel that will be limited by the amount of lift and downtravel is extended to the point where ball joints or axle CV joints may go into a bind.
I prefer to achieve a lift from quality coilovers and stay away from spacers!
YMMV