Advice on new rear leafs

I am new to the forum and have been reading up some things here and there but I need some advice on what kind of new Leaf springs to get. I am currently running on a 3.5" lift with blocks in the rear and want to upgrade the leaf springs. The problem is that I am having a friend build up a Rear tire carrier and bumper and I'am worried that a standard 3.5" lift leaf spring will sag from the added weight and I wont get the full lift amount. I thought about adding shackles if needed but didn't know if I would need shims or not to keep the drive line angles correct. I have heard mixed reviews from OME, rusty's and RE and I have no clue on what I need in my situation.

I also have another problem with my front end. I am using Tuff Country ez-ride control arms and it seems that whenever I go in reverse and tap the brakes the front end jerks a little.

Thanks

OK.

How much lift are you wanting?

What size tires? And are you going to use a full size spare out back?

Do you have a SYE(slip yoke eliminator)?

I would ditch the blocks if they are over 3/4" and totally if they are aluminum. Solid steel only. You can add a 3/4"-1 1/4" shackle pretty cheap.

I have Rough Country's 4.5" and I like them. They ride and flex pretty good and gave me 5" over stock and are still holding up good for 2 months so far.

I want to keep it at 3.5" of lift because I dont want to get into the SYE or a new drive shaft. I have 31x10.5x15 tires with a full size spare going on the back. I have a 1inch drop transfer case crossmember and i dont want to get a 4" leaf pack and have it not settle down all the way and then have driveline vibrations.

Ebays got some Pro Comp 3.5" full leafs for cheap. And Teraflex also had some on sale.
Id keep checking craigslist, here and other Jeep forums to see if you can find any used cheap.

you'll Definately want to upgrade from the blocks though.

is a 3.5" leaf going to be enough with the added weight of the bumper and tire? I dont want the rear end to sag. Also when adding just a leaf do you need shims?

Why dont you just wait till your done with the bumper and then youll know exactly what you will need!

Yeah it shouldnt effect it much at all. The aftermarket springs are a little stiffer than the stock packs anyways. And if it drops too much for your liking. Several places make a 3/4" shackle. I've got a Rusty's they're cheap and strong and they have a greasable bushing