Shackle and axleover question

[Justins83']

Okay so my 83' swb has a 4.5/6 in drop but still isn't level for some reason.It's spindles & springs up front and a axleover with a bolt in C-notch in the rear and Belltech drop shock all the way around.Well the truck came with a set of 2" drop shackles,if I put em on there will it lower it anymore or raise it?I did lowering springs and shackles and hangers on my old squarebody so i'm not really familiar with axleovers.Rides like a caddy right now

 

[crazy4offroad]

Longer shackles in the back will lower it, but only half whatever the length of the shackle is, because there are 2 mounting points for the rear springs and only one is being lowered. It will also move your rear pinion angle down a little.

 

[bigchevytruckdriver]

As far as axle over and shackle drops, as long as the spring rate is not changed it shouldn't affect ride quality very much. Unless a. the shock doesn't have sufficient travel to absorb the bumps, or b. you get all the way down to the bump stops. Both of which can be modified with either different shocks, lower shock mounts for A., and bump stops removed for B. As pp said the shackles will lower the truck but affect pinion angle as long as you dont go too long the pinion angle should be fine. Somewhere online there is a picture of the optimal pinoin angel with standard u joints and cv joints. IIRC for standard u joints the pinion should be close to parallel with the ground so driveline has some angle vs cv the driveline should sit very near flat. That being said I think the diff being rotated down a little will actually help.