stock 2013 ride height

I'm considering installing a leveling kit,most of the kits are a 2 inch,when I measure my truck now I only have an inch of difference between front and rear so installing a two inch spacer is going to make me nose high?

 

Yes. Measure the distance between the wheel hub and fender lip, front and back on both sides. I prefer a bit of rake with the rear a little higher than the front. If you're looking for spacers, they do make them in various thicknesses. The preferred method is with springs though.