Messing with leaf springs And Air Bags. Input needed!

[skidoo_j]

Long story short...   I'm SOA in the rear with metric ton springs (4/1) with XJ shackles and ruffstuff 8" perches,   I've been running a Stub and Slip shaft (sye w/o the double cardon).     I've ran this setup for 5 years and not been happy with the rear suspension.   Recently I put the MJ shackle back on and it's night and day difference in the rear,  I assume the springs are able to move and flatten more now...     

 

I do not want the extra lift that I obtained with the mj shackles installed, and at the same time axle the angle is now wrong, causing drivline vibrations.  Correcting angle with shims will give me more lift (3* shim 8" long is min 1/4" lift).  But I only want a 4" lift in the rear.     The axle is originally from an xj so it's 2 3/4" tube, current spring pack thickness   is 1 3/4", plus the delta in spring perch under to over probably 1/2".      So basically I'm trying to eliminate 1" of lift that I accomplished prior with the xj shackle....  6

 

 

My goal is just a 4" lift in the rear.     the axle is originally from an xj so it's 2 3/4" tube plus the spring pack thickness   is 1 3/4"   plus the delta in spring perch under to over probably 1/2".      So basically I'm trying to eliminate 1" of lift.  and I'd accomplished this prior with the xj shackle....  

My plan is to put new perches on to correct angle,  remove some lift with cutting the perches deeper (currently about 5/16" gap between spring center  bolt and axle so I can take 3/16" off here).   I'm going to roll the axle and go with a CV style shaft with a double cardon.     Do reduce the lift further:

 

I would like to remove the 5/8" thick bottom leaf and leave the top 4 leafs....      I have a set of airbags that are collecting dust that i could then add for when I haul something I don't damage anything.     

 

 

SO here are the questions for input.....       How Severe will the axle wrap be?    (perch is 8")    Would replacing the 5/8" bottom one with one from an xj that's the same length, but 3/16" reduce the wrap enough to benefit?   

 

 

 

What about possibly using slider boxes in stead of a shackle?   On road characteristics and usability are more important then off-road capabilities....   

My goal is just a 4" lift in the rear.     the axle is originally from an xj so it's 2 3/4" tube plus the spring pack thickness   is 1 3/4"   plus the delta in spring perch under to over probably 1/2".      So basically I'm trying to eliminate 1" of lift.  and I'd accomplished this prior with the xj shackle....  

[1989 comanche mj]

Slipper perches (Thats what they are called on trailers) slider boxes  are the way to go, they can handle the weight.  Thats how most trailers are setup. But you will loose some articulation and it will ride rougher than a properly setup shackle.  Lots of axle wrap if you remove the leaf.  Could remove the leaf and do a traction bar. 

 

I had this issue with mine, put an 8.8 in with very low perches, still lifted it even with stock leafs.  So I lifted the front.