carringb wrote:
These guys are an actual spring MFG. I have used them for several medium duty trucks. If they don't have an upgraded spring-pack in stock, they can make a new set pretty quick. Any heavy truck shop can do the R&R.
http://benzspring.com/
Ditto. Probably doesn't help you since you are in WI, but I've used Benz Spring on a few vehicles and their work is amazing. They will custom build what you need to get your ride right.
Perhaps the better, but more expensive option, might be to consider an Ultra Ride set up from Link Manufacturing. The cost is huge ($4-5k if I recall), but it is the cat's meow. Your rig is big and springs have their limitations, as you've discovered. We have this set up and it is excellent. Here's a link to Link, for what it's worth (look under the current models tab for your C5500):
http://www.linkmfg.com/ultraride.htmlGood luck.
'15 Ram Laramie 5500 w/ a giant Okanagan on board.