Puzzling Super stock spring issue

[oldkimmer]

Once u get it sitting right with the right wheel base do this. U have to also remember that the rear shackle angle will be different from side to side because of the arch of the springs. The higher side will have less angle. Also the top of the shackle has to be leaning ahead of the bottom. I’m not sure by how much but it has to be about 45 degrees or more. Make sure the U bolt torque is 45 foot pounds. That’s so the spring can do it’s job. Kim

 

[33 IMP]

Before I spent any money, I'd swap em side to side.....and see what happens. (I havent read the whole thread yet, but I bet somebody mentioned that the new ss springs are garbage).

 

[Lefty71]

Before I spent any money, I'

Honestly, I'd just drive the damn car first.... slowly at first of course, and see what happens.

 

[cbodybob]

Since it was just apart and you didn't personally do the work, I would double check the front spring hangers and make sure they are identical....there are many possibilities there and could easily explain that 5/8 inch difference.

Already done that. Identical

 

[cbodybob]

If the wheelbase is off and the chassis measures ok, which it probably does. 3 items to check between the two sides. #1; the front spring hangers are a different dimension from the mounting surface to the mounting hole. #2 the spring to centering pin is a different dimension to the front eye. #3; the axle isn't mounted correctly on the centering pins.
Doug

Done all that already. There was one measurement 1/2 inch off

 

[cbodybob]

If you don't find anything with the spring or frame, check your rear housing for overall bend. Back in the day after upgrading my 8 3/4" housing with as much aftermarket stuff I could buy, I still had problems.

Slicks, 3600lbs and 7k launches took their toll, and the last 8 3/4 housing I pulled out was bent over half a foot out of shape when pulled. Ended up changing to a Dana with thick wall tubes.

Probably not a bad idea to check that.

 

[cbodybob]

I agree, but wouldn't expect any better from a different one.
What's that called again when you do the same thing and expect a different result?

Yea I know but I can check it before installation & return it if not correct.

 

[cbodybob]

I wouldn't assume the car is shitty or you or the previous owner...
But the springs are.
Especially with a car that heavy and that much torque multiplication.
Had those on my Charger and they twisted up in no time.
If you could put a nice heavy full leaf under the main leaf, might work as a band aid.
As far as the rear shackle angle- if the pass side is flattened out, of course it will angle back more than the other side.
On the centering pin.. guess you would have to loosen up the u bolts and take a look. Is the hole on the perch bigger than the pin?
What's the rear-end out of.

I’m not sure. Usually B body rears fit J bodies nicely. But I honestly don’t know. I’ll measure it & see

 

[33 IMP]

If that rearend is truly 1/2 out of square, that thing will pull like a mutha to one side or the other.
Four wheel alignment check time.....

 

[cbodybob]

Once u get it sitting right with the right wheel base do this. U have to also remember that the rear shackle angle will be different from side to side because of the arch of the springs. The higher side will have less angle. Also the top of the shackle has to be leaning ahead of the bottom. I’m not sure by how much but it has to be about 45 degrees or more. Make sure the U bolt torque is 45 foot pounds. That’s so the spring can do it’s job. Kim

I’m at 28 degrees on the driver side & 36 on the passenger side currently with the ballast removed. I’ll have to put the ballast back in to be legal. I may step down a class also

 

[cbodybob]

If that rearend is truly 1/2 out of square, that thing will pull like a mutha to one side or the other.
Four wheel alignment check time.....

Yep

 

[RemCharger]

It's pretty common to use a 65 67 8 3/4. I put one in an aspen and it fit quite nicely.

 

[cbodybob]

It's pretty common to use a 65 67 8 3/4. I put one in an aspen and it fit quite nicely.

Yep

 

[cbodybob]

If that rearend is truly 1/2 out of square, that thing will pull like a mutha to one side or the other.
Four wheel alignment check time.....

I’m thinking spring. That’s what I measured.

 

[Dave6T4]

If I remember correctly, the original Imperial rear spring mounting plates were these Iso-clamp pieces with a rubber isolator on it. The spring locator holes in the plate were much larger than the centering pin in the SS springs. Guys used to weld an appropriately sized washer into this larger hole with with an inner hole sized to accept the spring centering pin. Maybe this was not done, allowing the axle housing to shift in the spring.

 

[cbodybob]

If I remember correctly, the original Imperial rear spring mounting plates were these Iso-clamp pieces with a rubber isolator on it. The spring locator holes in the plate were much larger than the centering pin in the SS springs. Guys used to weld an appropriately sized washer into this larger hole with with an inner hole sized to accept the spring centering pin. Maybe this was not done, allowing the axle housing to shift in the spring.

Correct. It’s been properly converted to the standard Mopar pin & shock plates. No issues there

 

[gkent]

Is one of the front spring hangers longer than the other? Using a forward reference point on each side, are the hanger mounting points in the same location side to side?

When I was taking my 69 RR apart I undid the rear shackles and the left spring swung over and damn near hit the trunk extension because the body mount - not the hanger - had been installed at an angle on that side.

 

[Lefty71]

Already done that. Identical

Soooo.... how's does it launch??

 

[dvw]

Done all that already. There was one measurement 1/2 inch off

And which measurement would that be?
Doug

 

[cbodybob]

Soooo.... how's does it launch??

Beats me