[CC69Rat]

Sumter - Realizing you're trying to make a bad (Previous Owner) situation better, we're here to help you man.

Two ways on the coil / Traling Arm / Truck arm suspension. It sounds like you know this, but when the truck is lowered, the pinion where it meets the drive shaft yolk that angle doesn't change much at all. So essentially what you'll run into is the pinion angle will point UP too far toward the bottom of the bed floor. We need t ofigure out a way to 'Roll" that pinion angle back down. you can accomplish this by:

Flip the front trailing arm brackets upside down. This will take away about 3-4" of drop that the truck sees. So, what I mean is by moving that hinge point UP - ( where the trailing arms meet the cross member) then you can lower the truck without changing that pinion angle. This will also help you with overall handling because the truck arms will be at (close to) stock angle. The front mounting point higher than the back. The only downside to this is it will cancel out about .75" of your drop. If you raise the front mounting points, then you also raise the angle where it meets the spring perch and it will raise the truck.

Otherwise when you lower it, the trailing arms will essentially be laying purpendicular to the ground. .. and the truck will be bad to squat in corners and hard acceleration. This is even more important with a LWB .. just my opinion.

The next option as you mentioned would be shims. you can buy pinion shims for the truck trailing arm suspension. 4 deg sounds about right. I usually do 1 deg per 1" drop. .. on a SWB, but on a LWB it might be slightly different. You want a little bit of nose up on the pinion so when you take off the pinion will roll DOWN. .. and the drive shaft and pinion angles will 'zero out' I usually do 1-2 deg UP at ride height.

On the drop springs, yes .. absolutely. Heated springs are dangerous brother. Not trying to make a situation worse for you but what I'd do would be maybe a 4-5" drop spring .. and a 1" block ? then maybe 3 or 4 deg shims. If you're around 6" drop or more, I'd consider flipping the front brackets AND shims. I happen to have some extra front brackets if you need them. They are ROUGH to get out of there but it definitely helps wit hsituations like yours. while you have the drive shaft out it would be a great time to throw a new Ujoint in there .. Hint.

Later. Let me know if I can help you.
Welcome to the Board!
Chad