Caltracs WERE NOT designed around a mono leaf setup. It doesn't hurt to have a split mono setup though. It also doesn't hurt to have leaf spring sliders also. One good part on top of another just progressively makes your suspension work even better.
And if you do go to a mono leaf setup, I would NOT do it on stock leaf springs. That will make everything worse. Ride will be horrible, load rating will drop, and ride height will be adjusted also. Just a plain bad idea.
If they make a split mono design than yes go for it (you could still tow I am sure). But with my search I do not see a split mono setup for a fullsize silverado/sierra. Probably because many have not shown interest to manufacturers to produce such item.
What shocks do you have in the rear? are they adjustable. I may have overlooked that piece of information.
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