You could do that I guess. Springs wear as they work over time. For how cheap a new set of coils are I'd rather just replace them, they could probably use it. When I went with the HD "UpCountry" rear leaves and heavy duty MOOG front coils my measurements were 19.5 at each corner with the rear end riding a little higher than the front it looked. The rear springs have settled in a bit and I'm riding at 19ish inches in the back.

 

Is the front equal on both sides? If it is, and you're committed to changing the leaf springs, why not see how far the Generals raise the rear.

 

Take note of the floors above the brackets when you're under there. If the floors are rotted out (as mine were), you'll get some nice burn holes in the carpets or melted trim pieces if/when you take the torch to the bolts. The original bolts had a lot of red loctite on them, so you WILL break the weld nut if you don't use heat and the old springs are original, regardless of the rusted/seized bushing situation that's very common.

I recently did mine and I had to cut the bushings out on the front on both sides, split the metal bushing and then heat the bolts. I used a lot of heat on all 4 of those bad boys. I bought new Mopar bolts in advance, burned the red loctite off of them and used some blue loctite in case I ever need to get them off again.

I went with the Dorman springs and they've been very nice for the last 6 months or so. They've only recently started settling a bit.