Before I get flamed, I have done a search and didn't find what I was looking for. I am trying to determine if I could do a front shackle reversal on my '74 J-20 by just putting the shackle at the rear of the front springs and bolting the front of the spring to the original mount.

Here's why i'm contemplating it. I did a soa up front with a shackle flip, 4" blocks, and a helper leaf in the rear, and I've got 2" of rake...to much for my taste. I welded my perches on with the pinion pointing directly at the t-case, so I've been told that my caster will be whacked.

If I just move the front shackle to the rear of the front leaf springs, will that lower my pinion angle, and give me the extra height I need? I already have to lengthen my front driveshaft, so that is not really an issue. It seems like it would be fairly simple and straight forward to do...3 bolts per spring.

Has anyone done this without welding on different mounts?

no, you can't:flipoff2:

springs mount INSIDE of a spring hanger while a shackle mounts OUTSIDE of a shackle hanager, one is solid on the inside and one is "hollow"

On my FSJ, the shackle is shaped so that it goes inside the hanger, and the spring goes on the inside of the shackle. I guess I will have to measure width on the hangers. They are both open triangle shaped hangers.

Yes, you can do it with any FSJ or any vehicle that uses "Y" shaped shackles, but I doubt that it will work out, I don't see you gaining any lift from this setup unless you lower the front spring hanger, negating any caster change.

A friend of mine bought a YJ with a crude home brew SOA, the guy was more concerned with pinion angle than caster, bad, bad, bad. First of all, front pinion angle is only a real issue with a huge lift and short front shaft, in the case of that YJ, a three foot driveshaft and a high pinion front axle, who cares about front pinion angle, make it steer right.

Try it out on your FSJ, but I wouldn't be surprised if you end up rewelding your axle pads in the right place. If it comes out close you could use some custom built steel shims to get caster spot on, but be sure to weld them to the axle or make sure they can't shift. This does give you a way to run reversed shackles and have a decent approach angle by angling the front spring up towards the bumper.

By the way, why bother welding pads on top of your J-truck housing when you can swap all the guts out into a Chevy truck housing that already has SOA pads setup to bolt in to your truck? Then just look for taller springs to acheive your desired height, or longer shackle with lowered main eye attaching point.

Hindsight is 20/20. I have also thought about putting in chevy rear shackles up front that would gain me around 3/4", but that will throw my angles off even more. I do have a pretty tall rig now, and the driveshaft is short. So that is why I had a brain fart and decided to crank up the pinion to compensate. I guess I will have to deal with the consequences later when I actually get to drive it and see what happens.