Weird rear spring mounting

[fireguyfire]

I'm about to drop the rear end on my newly acquired 73 challenger as I go through it, change rubber brake lines, shocks, etc etc.
This car has been tweaked to go fast, and the rear spring mounts have been modified. On the rear of the springs there are beefier shackles, and on the front they made it way different. The spring has a different front spring bracket, the normal frame mounting point has been removed (you can see small holes where the spot welds were) and the front of the rear spring mounts up through the floor of the car, as opposed to forward. There is a reinforcement plate in the inside floor of the car to accept it.
The car came with new factory spring attachment braces to weld back in (they are 2 pieces) for each side.
I'm going to drop the rear end and put it back to stock with the new frame brackets, but I'm curious if anyone knows why you would do this? It is definitely deliberate and not because of a rot issue or anything like that; the car is rock solid.


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[dodj]

I would guess it was somebodies idea of how to lower the rear of the car? I can't see any other benefit to doing that?

[Cuda Cody]

 

[anlauto]

 

[JonH]

Does it change the front pickup point? IE are the springs longer or shorter? Are they even Mopar springs?

[fireguyfire]

How could I tell?


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[JonH]

Is the front mount in the same spot as the OE mount would be, or is it further forward or behind? Changing this point is how drag racers tune rear suspensions for differing track conditions, car weight, center of gravity, etc. etc. This is why 4 link suspensions became popular in drag racing. Gives you an enormous number of adjustments, most of which are unusable. In your case they may have changed that point for traction purposes, or they simply thought doing what they did was a stronger option that the stock mount...

[fireguyfire]

The front bracket appears pretty close to the factory position, just turned upwards; it also appears to be a factory front bracket except they've remove the studs and used bolts to mount it.
The only thing that seems a bit off is where the pinion snub is in relation to the snub spot on the tub.
The car is a Rallye Package car which meant a beefed up suspension.
Is there anyway I can prove these springs are originals or not? Markings, mrleasurements from eye to eye, etc?

[fireguyfire]

Here's some pictures; the car is obviously on a lift, but the pinion snub seems back a couple of inches from where it's marked the factory undercoat; although the rear end is hanging so that might make a difference.
5 leaves in the rear springs.


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[JonH]

Others on here can help with that. Should be part numbers on them though. I do know the super stock springs are shorter. Is the rear mount still stock with stock length shackles? My guess is the pervious owner did not trust the OE mount with spot welds, and thought his option was stronger..

[fireguyfire]

No, it has different beefier shackles; my plan is to put everything back to stock.


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[HP2]

Is the original structure these bolted into still intact? If it is gone, maybe it was damaged and they cut it out and remounted them where you see them. If it is still there, you should be able to relocate these to stock position.

Judging from where I think that hanger is positioned and combined with the snubber position, it looks like it is all moved back a couple of inches, but that would put the shackles into your valance almost assuredly.  Maybe they did it to use A body springs, but that wouldn't necessarily move the snubber back.  Why anyone would want to do this is beyond me, but you never know what kind of backyard engineering you can find after  4 decades.

For a spring check, the E body leaf should be 57" overall length, eye to eye. The front section(eye to axle mount) is 22" and the rear section (axle mount to eye) is 35".

[fireguyfire]

Perfect; great information.
Those measurement from center of the eye to the rear axle location, are they straight line measurements, or around the outside arc of the spring?


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[fireguyfire]

So I've removed the rear lower valence and am about to drop out the rear end; here is a picture of the beefier rear shackles


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[JS29]

Mice apparently made a home inside your frame rail!   :pullinghair:Dame rodents