1985 K20 lifted with 8" rear springs. Want to lower it down to 4" lift. Looking at the prices of replacement 4" rear springs vs. a lowering shackle that says it'll drop it down. My question is would a lowering shackle do any good on a mud truck? (Yeah, it's for the mud.... sorry, but that's my style.:flipoff2:) How much would limit travel, articulation, whatnot... Someone else out there must've tried this before. Ideas, suggestions?

Well, it will turn your pinion angle down. I'm assuming the bed is gone,
to allow the drop shackle...
Better to get the springs. check the classified section,
you may find someone willing to trade for 8" springs...

no, the bed is still on, and plans don't include removal. I have about 3 1/2 to 4" of room below the bed above the top of the shackle. I can only find lowering shackles that lower 2".

Here's the longer version of the situation. 85 K20 4" lift in front. Big hub 44, big block 454, turbo 400, 203, 14FF, 8" (or 10"!?!) lift in rear. 38 tsl's. Came this way when I picked it up, mind you. Bought it for the big block and 38's. Looking to level it out and run 35's. Also, looking to do it on the cheap. Rear springs are about $320, plus $35 for u-bolts. Lowering shackles are about $50 shipped. I think the rear springs are 8". I pulled the rear driveshaft due to the fact that it was holding the rear of the truck from moving at all! The shaft was way too long and the rear bounced around like a pulling truck! So, I'm assuming the rear springs might be 8" that just haven't been able to "settle" down yet.

I can only assume the rear and front height lifts as I don't know what was put into the truck before I bought it. I used my other truck (with a 6" spring lift) as comparision. I measured the distance from the top of the axle tube to the bottom of the frame both front and rear on both trucks. The 85 has 2" lower in the front and 2 1/2" higher in the rear. I pulled the driveshaft out of the rear and it didn't sag at all. So, I guess my question is, what should I do?

i would go to the classified section and post: wanted to trade- 8" lift chevy rear springs for 4" lift chevy rear springs. that would be the cheapest. there should be plenty of folks wanting more lift who already have 4".