have 2 hi mileage Dakotas. Both 318 club cab/ one 96 4wd, the other 92 2wd. the 96 needs the a$$ lifted a couple of inches, and a lil more capacity. The 92 sits pretty nice, but could use a bit more capacity. at any given time I do tow with both trucks. sometimes a pop up camper with a bedload of camping gear, sometimes a 6-1/2'X13' utility trailer, usually with 1 or more garden tractors on the trailer.
I've done add a leaves at home (on a 94 reg cab/short bed Dakota I used to have) got those leaves from EPay. have removed original leaf springs on a few cars and took the spring packs into the spring shop for a "bench rebuild" and reinstalled them. Have replaced with new on other vehicles. While both of these trucks are well maintained (at least since I got them) and both are over 200K miles on original springs, no leaves are broken, might just be a bit tired. (though I don't have a brand new, square body Dakota to compare to) I plan to run them both into the ground.
Anytime I have to work on them, I work on them like I am gonna have them "forever", no baling wire/ chewing gum style of repairs. always buy the best quality parts I can get. I have everything I need for a total front end rebuild, going to be renewing the entire front suspension on the '92 with all MOOG parts, and then sent for alignment, as soon as my son gets his Ramcharger off my lift. I did the whole front end on the 96 last year. (I used to be an alignment guy for ~15 years, currently a fleet mechanic for the State, have all the tools, and well within my capability.)

don't really have the cash for 2 new sets of leafs, and anyone that sells them, seems to only sell "stock replacements". I want a bit better. I do have my own 2 post lift at home, made doing the add a leaves on the 94 a piece of cake.

Now the back story's done, here goes;
when I have taken springs in for a rebuild, they add a leaf almost as long as the main leaf, looking at add a leaves they mostly sell "short" versions. I found 1 company with both "short" and long" versions. I sent them an E mail their short is 24" their longs are 36" most "shorts" are 20-22" that I have seen. they claim these shorts to give 1-1/2-2" lift while beefing capacity.
Even my 2 Diplomat ex squads, they added full length leaves. one had busted front eyes, they just added new main leaves to the original spring packs, after cutting just the remnants of the original spring eyes plus maybe 1" more. but the spring shop was bought out, and their prices have gone stupid. Cheaper to buy new springs than to have them add a leaf. Even if I pull them and re install them. so I want to do my own add a leaf.

Which is better, and in what instances. Whether ride is the #1 goal, or lift is the goal or extra capacity in the bed/better towing capability. Short add a leaf or long?

I have read on some of the 4wd sites, where the readers have built their own "b@stard" leaf spring packs. Strangely, either a Dakota or Cherokee winds up the donor for any brand of truck.
I have a pair of used leaf springs and 1 brand new one from the back of a '90 W250. We put brand new ones on this truck, another of my son's trucks. (only have 1 kid)
same width leaves as the Dakota, plenty of material there to play with. Depending on whether I go "short" or "long" add a leaves, I may be able to get the material for both sides of 1 truck, from 1 of these W250 left over springs.
also I don't want to screw up pinion angle on either Dakota. Any tips to eliminate that issue?

Why not supplemental air bags?

(just curious, sorry)

long springs are soft---short springs are stout.....

As long as you are not cutting the spring perch off the axle, I doubt your going to add enough spring lift to change the pinion angle much, unless you interchange the 4x4 axle for the 2x4 axle. The 4x4 axle should be mounted under the springs, and the 2x4 axle should be mounted above the springs, swapping those would really change your pinion angle.

The thickness of the spring leaf you are adding is as important as the length. Thicker leafs add more capacity.

From your extra spring packs, add a matched pair (read that as 2 the same length and thickness) of long spring leafs to the truck that needs more lift, and a pair (or 2 pair of different lengths) of shorter matched spring leafs to the truck needing more capacity. Don't forget to pick up a couple pairs of spring center bolts, and I would also pick up a couple pairs of the spring alignment brackets to add at the front edge of the newly installed extra springs in each pack. Gene

I don't have them.... and that would certainly seem like overkill on a Dakota, wouldn't it?
trying to use some of what I have laying around. the extra parts I have are going away soon anyways, so I thought I'd get some good out of them instead/in the meantime.... get some use out of some, less to get rid of... and cash ain't very available right now..... got stuck for final expenses for a brother in law that passed away, I'm up to my neck in bill$ right now as a result....

no, not swapping rear ends. Both trucks are daily drivers, wife drives the 4wd I drive the 2wd at the moment.....
yup I know about the center bolts, no biggie there, and the alignment brackets/ clamps to hold the spring pack together so the leaves don't fan out. figured on those. and new U bolts.
and I have a chop saw to equalize length of what ever leaves that I decide to use.....
when I had my 75 Cordoba I had those springs redone, and wound up with pinion angle issues, all they did was to re arch and add a long leaf. same thing they had done to every set of leaves I had done by them, and only car that gave me that problem afterwards.

these trucks have the 3 leaves with the heavy (like 2x thickness) short one on the bottom, edges of which only touch the bottom leaf of the other 3 when loaded. Im on the computer, not under the truck at the moment but I think that heavy leaf, while on the bottom, is longer than the 3rd leaf. was gonna add in my new leaf either between main leaf and 2nd leaf. or between middle leaf and 3rd leaf.
and Yeah, I know about staggering lengths progressively from longest (main) to short.

and looking at 70s and 80s trucks (and prior) I remember the 3/4 and 1 ton trucks had as many as 8-10 leaves then a sub pack of 2-3 leaves ("overloads") where the newer trucks Ive seen "1-ton" trucks with as few as 3-4 leaves total, with no "overloads" this makes no sense to me. (Yeah I know this thought has no bearing on what I am trying to do here)

As said, just curious. I can more than appreciate using what you have and save some $$$$!

I was thinking airbags mainly because of how light the tail end of a Dakota is (unloaded). I thought that maybe the airbags would provide a happy medium between capacity and comfort.

yeah not a bad idea....

And or make yourself some custom shackles.

ok next Q.... any sources for the clips that hold the leaves together and keep them from fanning out, plus center bolts and the inter leaves/ whether zinc or plastic? what diam. center bolt for Dakota, 5/16 or 3/8? dimensions for U bolts? Ive gotten them from local spring shop before but they close at 4, I get off at 4, 30 miles away.... so I can't get there w/o taking time off of work.... if I can get dimensions maybe I can order ahead of time? I want to have everything on hand before I start, can't have truck down longer than it actually will take me to do the job, also the local spring shop wants an old U bolt as sample, can't get that until I'm tearing it apart..... they used to make them on site.

Re arch them!
1) Sledge hammer
2) big jack stands or maybe 2 pieces or RR rail.
Dont forget ear plugs!

De arched a set of d150 springs this way when I was $$ down. Probably the hardest thing is going to be able to keep the Springs upright when hammering them maybe somebody with a big set of gloves to hold on to the spring every time you lock it or maybe some rope tied to it..

Red neck.. Yes! Cost effecient...yes!

I took the springs from my 78 Sport Fury into the spring shop when I got it, asked just for them to rearch them. Didn't cost me much, but didn't last the rest of that season either. Only time I ever "just" had a set reached w/o adding a leaf. wound up doing the 80s high school patch..... air shocks. don't like my Mopars looking like 70s GM's seems every one of those cars looked like they were dragging @$$. Out of this set of springs that came from my son's 90 W250, I hope to get a pair for each Dakota (2) and a pair of add a leaves for that car. no leaves were broke on that truck. it sat decent and took a load pretty well, but my son makes more $$$ than ol' Dad, so he decided to replace them when he put the flat bed on.
Im gonna do the 96 4wd Dakota 1st, went by the spring shop today and picked up the new center bolts, spring clips, inter leaf pads and U bolts..... the Fury will be last, because I haven't even got it out yet this year, its stored 30 miles away in Mom's garage.