I compared the 2 "pack springs, the ones with the rivets and rollers.
Both springs have an identical arch.
The one on top is from the lift pack. It's shorter but the tabs for the rollers are longer. This allows the leafs to separate at full droop. I don't like this.
The stock one on the bottom is longer and the tab is shorter. This will keep the pack together as the axle droops.
I'm going with the stock spring here.
Now we're talking hybrid custom springs.





I reused the factory bumper mounts by welding them to the C- channel.
