Superlift springs

[squarebfan]

I have a 86 k20 with 8" superlift springs on it, as well as a duramax engine installed. I've recently noticed that the driverside is saging about a 1-1½ from fender well to tire if I remember correctly. What do think is causing it D-side leaf failing?
I've measured everywhere I can think of on each side of frame, leaf spring bolts, frame to top of axle and all measurements are equal.

 

[nvrenuf]

Gas in the pass side tank making it lean?

 

[squarebfan]

Its the d-side front that is sagging down.

 

[bucket]

How old are the springs? Seen any air time?

^That's a serious question, not a joking one.

 

[squarebfan]

Brand new springs
Only been driven on 5 months other wise been bolted onto rolling chassis while being built for 4 yrs

 

[bucket]

Brand new springs
Only been driven on 5 months other wise been bolted onto rolling chassis while being built for 4 yrs

Kind of annoying, but you can swap sides and see if it tranfers.