Moparguy thanks for the write-up. From my post you responded to the other day, my 3600 has the same front end sag. I was going to either re-arch or replace the springs but after reading your post I'm going to try this first.
You're Very Welcome! Sharing what does and doesn't work is what makes forums (and The 'Bolt especially) such great places to hang out.
I grin every time I drive since making the changes. One thing I would recommend is have new u-bolts, rear spring eye bolts (possibly bushings), and front spring shackle bolts on hand just in case they're needed. If your truck is like many and has the typical unknown mileage (but it's likely a lot) I suspect you'll need them.
Good Luck, and be sure and report how it works.
RonR
PS, As mentioned in the original writeup, due to the new u-bolts being 1/2" rather than the needed 9/16th" I did reuse the originals. The threads were good and after cleaning all looked good. What I didn't mention is that with the extra spring, the originals are too short to get a full nut with the bump stop in place. It fits under the u-bolts on top of the axle spring plate (bolts needed to be about an inch longer). My solution, I left the bump stops off. So far so good, but if I ever bottom the suspension out it'll be metal on metal. And if I'm ever off road and going fast enough to bottom out, well I needed to SLOW way down. It'll be a lesson to remember for sure.
