Leaf spring relocation shackle

[68ChargerJMP]

I installed the relocation boxes but I have not installed the rear shackle hanger portion yet. I noticed if I locate /align the hole in the frame to the same position as the original hole, there will more frame  above the new hole compared to the original location.  My question is this: Will the shackle have enough travel back and forth now, or will I need longer shackles? I dont want to raise the hole in the frame because that would add ride height. I'm not sure how much back and forth  travel is required. Any ideas? Thanks.

[HPP]

Raising the hole in the frame actually lowers the car because you are tucking the suspension up higher into the car. If the hole you are installing now is equal in height to the original, you should not be changing ride height despite there being more visible frame above the hole.

The leaf does not require a great amount of travel in the shackle to be effective as it only moves a couple of inches. You want the bottom of the shackle to point backwards from vertical about 30-45*. This gives it the range to push backwards as the spring compresses and forward as the spring unloads without going over center.

[RallyeMike]

I would not worry too much about ride height changes. Remember the axle is forward of center on the leaf spring. If you raise or lower the rear shackle hole, the axle height change will be less than half of that.

[68ChargerJMP]

Thanks guys.
HPP.....I meant to say the frame below the hole. I've been looking at it upside down for too long. If I align the hole on the frame the amount of metal BELOW the hole will be taller which looks like it may interfere with the shackle movement. I prob should post a pic to explanation but I will have to take one of that area.

[HPP]

Pictures certainly help.

[68ChargerJMP]

Here is a pic of the area I am talking about. Sorry for the Kindergarten drawing but....

Yellow circle marks where the new shackle hanger tube would sit in the frame rail. Notice the height difference of metal below the stock location and future location ( Car is upside down, so it appears to be above the hole). My concern is, the shackle will not have enough movement before it hits the frame rail because of this thickness. Does this help?

[HPP]

Okay.  I see what you're saying. Yes, you may run out of shackle motion before the leaf eye bottoms out. There actually are a couple of options here.

If you retain the shackle, you should duplicate the measurement of the original location in the new location. Yes, this changes its relationship to the ground, but the net gain in ride height is not 1:1. This is because mopar springs are asymetrical  and once they are loaded with weight,  a 1" change in the shackle location may only change actual height of the car 3/8".

Another option you have is to use a leaf spring slider instead of a shackle. The slider will mount on the bottom of the frame rail and will bring the leaf eye 2-3" closer to the frame than a shackle will allow, but still give it the range of motion it needs to move. This could net you a 1" drop in overall ride height.

[68ChargerJMP]

Yeah, I am aware of the less than 1:1 gain/loss because of the asymmetrical springs, but I really don't want to increase my ride height at all. Matter of fact I'll be ordering some drop leaf springs in the near future. I guess I could compensate the hole location difference into the spring drop, but that really doesn't seem like its a good idea. I have seen many a Mopar article where they did this same relocation deal and no mention of shackle issues were mentioned, so maybe I'm worrying for nothing.

I've contemplated the sliders, I just cant seem to find any decisive info. concerning the slider noise. Some say they are, some say they aren't.

Anyways..........Thanks HPP for all the info.

[1974dodgecharger]

curious are you using the US cartool shackle relocation kit?

I plan to do that to my car this year and wonder if I will run into this issue with the hotchkis setup.

[68ChargerJMP]

No, they are actually Magnumforce Racing boxes.