im looking at a rough country 5 inch suspension lift. I got a buddy that will help me put it on after I get some body work done first. my question is what amount of backspacing on my wheels would I need for this lift? im gonna run 315 70 17 with the lift like I am now under cranked torsion bars thanks

 

Around 4-4.5" of backspacing.

 

my buddy suggested to me that instead of buying that lift we could buy just lift spindles and blocks instead of that whole kit. my buddy also runs a custom shop here

 

I'd get the kit, I think you are talking about the same kit that is on my truck, if so, it looks sexy on the truck:

http://gyazo.com/518351ba79c984aa5f8413fa848853b6
http://gyazo.com/849ec9e1014bf2cc177fc237d0055fc6

 

I hope your buddy doesn't run a custom suspension shop.

Lift spindles are for 4x2 only, they won't work for you.

 

Those tires will fit with a torsion lift/level and nothing in the back. My expy was smaller, stock, than your truck - so my 3/2 lift would be comparible to your truck, levelled. See photo of my expy (on right, with those size tires) against a levelled '02 SCrew