Converting to a Spoa suspension system is allot more difficult than most people think.
If your going to use a kit I'd recommend a weld on kit. The bolt-on kits are a bit sketchy.
If your going to use a weld on kit, or just fab up your own, Make sure you get your caster angle correct, or it will wander like a pig.
DON'T rotate your axles. I REPEAT. DON'T ROTATE YOUR AXLES. Keep your axle flanges at the exact angle as the factory set up.
No kit is truly complete, so you will need to add additional parts.
Like a track bar, full high steer, long travel shocks, drive lines, or spacers, etc. The list of additional parts is dependent on the supplier of the kit you choose.
Your only going to gain 4.5" or so from a SPOA conversion.
To gain the other 3" you are trying to gain I'd recommend a shackle reverse kit from Calminni. Then a 1" shackle lift. Don't try adding lift springs to a SPOA, lift springs will defeat the articulation gains a SPOA ads. You need flat springs for max articulation.
Once you have all the parts installed you will need to do a dial in.
Then you will need to re gear the Zeke. A 6.41 will work for 31s.
My best advice is RESEARCH, RESEARCH, RESEARCH.
There are many articals on this board and others.Study them......
Here is one of my Zukes. It has 7" of lift SPOA, shackle, SR, 1" body, ETC. ETC. ETC.
These pictures were taken before the SR was installed.......