I put some 2wd F-250 Diesel springs (moog 844) on the front of my F-150, I only gained about 1/2"-3/4", but thats because the springs I took out had the coil spring spacer things in them.

It barely stiffend it up, it mainly made the ride alot more predictable and feel alot more sturdy. It actually makes it a pleasure to drive now. I say go with it if you want a small cheap lift.