2001 blazer 2wd lift
 

Will a 2.5 in spring spacer in frount and 2 in shackles in back fit 31s??

You can't do a spacer in the front of an s10. It won't allow the spring to seat properly or pretty much stay where it should. That being said, I think 3 inch springs and a 2 inch shackle should be enough.

So your saying if I do that I'm gonna have to get me front alligned? But what about lifted coil springs??
Then why do they make them?

I mean you'll have to get it aligned no matter what you do, but the lower control arms and the coil buckets on the frame aren't deep enough to use a spacer, cuz then there will be nothing to hold the coil spring in. At least that's how I understood it on s10forum.com under their 2wd lifting section. They do make lifted coils, and lifted spindles, but I believe that the spindles do not work with dual piston brake calipers, so you'd have to swap in the older single piston calipers or pickup calipers. I'm not quite sure why they make a spacer, unless its like a "universal" spacer for several different vehicles, but either way, I'd look into it before getting spacers and installing them, then driving down the street and have your coil spring come out. Unless your into that sort of thing. I bet it'd be one hell of a ride!