http://www.sky-manufacturing.com/chevy_gmc.htm
this kit has lead me too great confusion. if i want 8" of overall lift do i get blocks for the front and springs for the rear? or what?  

Blocks should really be avoided as they lead to increased spring wrapup. When you do use them, avoid them in front and limit them to maybe 2 inches or so tops in rear.  

ok, but if you looked at the kit it says it adds six inches of lift to the front. so what should i do to get six inches of lift in the back. i cant just buy half a lift kit?  

You can use front and rear leafs with a higher arch and you could do a shackle flip in rear of truck too. Some kits use block because they are cheap but it is a very poor way to do it.  

If you look right on down from the solid axle kit they sell a shackle flip for the rear that will give you around 4 to 5 inches.....do that and slap a 2 inch block in the back and your good to go.
DK  

also on a side note make sure you buy a 2 inch block kit that comes with angled blocks to get the increased pinion angle that your gonna need...good luck!
DK