I just got my parts for my sj410 in from HAWK. I was getting a water pump a timing belt so I thought I would get some spring perches and longer brakelines. I thought the perches would be thicker. I set them on top and did some rough measuring and added the thickness of the leaf springs and it looks like it will lift it just over 4" . Will this be enough to clear 31" tires. Also if anyone has done this on the narrower sj what backspacing should I get. I want to run an 8" wide rim with  31x10.5s . Is my steering linkage going to rub on the leaf spring?

Shouldn't have a problem with those 31's, I have a SPOA on an SJ413 and run 32" Swamper radials on a 7" rim. I can't help with the back spacing as I have the Sammy, that and I have some 1" wheel spacers which I probably would not need if I had the proper back spacing.

Shouldn't be an issue.  When I picked my 410 up it had 30" tires with stock rims and a standard SPOA and didn't even come close to rubbing.

I switched over to the wider SJ-413 axles and use 3.5" of back spacing as was able to run 33x12.5" tires with very little rubbing.  Nothing a hammer didn't fix.    I would stick with the 3.5" of back spacing on 15x8" tires.  That seems to be a pretty standard and won't cause to many problems when you eventually switch your axles out.

The Hawk pads seem kind of small, but they are the same as the stock.  I kind of like the Sky Manufacturing pads as they have the plates that wrap around your axle and attach to the stock mounts for a bit of extra strength.