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How low can you go

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Questions on my new toy.

Just bought a '73 Challenger, in general in great shape, but trying to figure out a few things. 318 slapstick auto.

1. It sits really low. I looked underneath and the leaf springs are straighter than any board you'd find in home depot.
- My guess is the leaf weakened and instead of changing the spring he just lowered the front end to match.
You can see how low it is in the pictures.

2. Near the shackle there's a piece loose, looks like it should be bolted in. What's it for?

3. Rear end identification. The foundry number is 2881489. So I assume it's a 489, 8-3/4"
But there's a 9 foundry mark also. I didn't think there's a 9" for that, but not sure.

4. gear ratio. I didn't find a tag on the differential bolts. I think stock they all came as 3.23.
I haven't spun the shaft to tire ratio yet.

5. Height, I think the body side should line up just below the center of the tire?

Recommendations:
At this point i'm thinking replace the rear leaf springs and then tightening the tortion bars to bring the car up about 4 inches/

Carl

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heminut

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The normal ride height from the factory had the rear leaf springs pretty much flat according to my older Direct Connection chassis manual.
 
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So why is it sitting so low? the rear shackle is about 2 or 3 inches. Didn't measure it, but I can't imagine they put a shorter than normal in? Maybe. too much to be just tires. I believe it originally had F70 -14 in the front and F78-14 in the rear. They put the P225/60R14 on the front and back
 

toolmanmike

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Questions on my new toy.

Just bought a '73 Challenger, in general in great shape, but trying to figure out a few things. 318 slapstick auto.

1. It sits really low. I looked underneath and the leaf springs are straighter than any board you'd find in home depot.
- My guess is the leaf weakened and instead of changing the spring he just lowered the front end to match.
You can see how low it is in the pictures.

2. Near the shackle there's a piece loose, looks like it should be bolted in. What's it for?

3. Rear end identification. The foundry number is 2881489. So I assume it's a 489, 8-3/4"
But there's a 9 foundry mark also. I didn't think there's a 9" for that, but not sure.

4. gear ratio. I didn't find a tag on the differential bolts. I think stock they all came as 3.23.
I haven't spun the shaft to tire ratio yet.

5. Height, I think the body side should line up just below the center of the tire?

Recommendations:
At this point i'm thinking replace the rear leaf springs and then tightening the tortion bars to bring the car up about 4 inches/

Carl

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It needs springs and the torsion bars adjusted up. Check out ESPO Springs and Things for your spring and hardware needs. I had great luck.
 

Chryco Psycho

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You have a 8 3/4 diff with the later 489 casting carrier , but gear ration could be a number of choices
There was a shipping mount for tying the car down on the rear frame rail , the loose piece is probably part of that .
Challengers typically sit quite low , no way I would raise it 4 "
 
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You have a 8 3/4 diff with the later 489 casting carrier , but gear ration could be a number of choices
There was a shipping mount for tying the car down on the rear frame rail , the loose piece is probably part of that .
Challengers typically sit quite low , no way I would raise it 4 "
Thank you. I need to raise it some. It rubs over uneven roads and I need to cross railroad tracks where I live. I'll raise the minimum to assure I'm not dragging. Appreciate the response.
 

toolmanmike

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14" on top photo and 15" on the bottom. The tires in the top photo were Mickey Thompson fabric belted radials.
(not steel belted) They really worked well and made the car corner like it was on rails.
 
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6PKRTSE

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I didn't want the jacked up look on my car with 30" tall tires. I have a 1/2" lowering block (welded in 100% around the perch and perch boxed in) and also Caltracs -1" split mono leafs. Sits slightly lower than a stock ride height.

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.

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14" on top photo and 15" on the bottom. The tires in the top photo were Mickey Thompson fabric belted radials.
(not steel belted) They really worked well and made the car corner like it was on rails.
Nice cars. Those are sitting considerably higher than mine, the midsection is at the center of the axle or slightly below. Thanks.
 
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I didn't want the jacked up look on my car with 30" tall tires. I have a 1/2" lowering block (welded in 100% around the perch and perch boxed in) and also Caltracs -1" split mono leafs. Sits slightly lower than a stock ride height.
 

cuda joe

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when raising the front take all the weight off the suspension before adjusting the torsion bars and count the turns on the adjusters .these cars sat a little low in the rear from the factory where does it rub ? what is your wheel width and offset ?
 
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when raising the front take all the weight off the suspension before adjusting the torsion bars and count the turns on the adjusters .these cars sat a little low in the rear from the factory where does it rub ? what is your wheel width and offset ?
Cuda Joe, I rub (muffler hits the ground) going in/out of my garage, if I get off pavement and run on a rough surface. The muffler is installed correctly, one side is sitting slightly lower than the other, but they're both tucked up tight enough that it shouldn't be an issue.

I have very little ground clearance.

I just ordered replacement leaf springs and had them put on a 1" lift. I figure that'll bring the back up 3"-4", then I'll bring the front up to a normal height. Thanks for the tips on raising the torsion bars.
 

HPP

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Questions on my new toy.

Just bought a '73 Challenger, in general in great shape, but trying to figure out a few things. 318 slapstick auto.

1. It sits really low. I looked underneath and the leaf springs are straighter than any board you'd find in home depot.
- My guess is the leaf weakened and instead of changing the spring he just lowered the front end to match.
You can see how low it is in the pictures.

2. Near the shackle there's a piece loose, looks like it should be bolted in. What's it for?

3. Rear end identification. The foundry number is 2881489. So I assume it's a 489, 8-3/4"
But there's a 9 foundry mark also. I didn't think there's a 9" for that, but not sure.

4. gear ratio. I didn't find a tag on the differential bolts. I think stock they all came as 3.23.
I haven't spun the shaft to tire ratio yet.

5. Height, I think the body side should line up just below the center of the tire?

Recommendations:
At this point i'm thinking replace the rear leaf springs and then tightening the tortion bars to bring the car up about 4 inches/

Carl

1.Yes, in their installed position the leaf springs should be almost flat. They may have about 1.5-2" arch in them, max, when brand new. You can replace them, but you may not gain more than an inch or two of increased height, unless you current leafs are really, really fragged. You also don't mention how many leafs are in them. If you have the light duty 4 leaf version, then yeah, they are going to bottom out easily and you may want to get a set with a higher leaf count (the factory XHD would be good for this. But they aren't going to lift it 4 inches. If you buy leafs with 4-6 inch of free height, when installed they will flatten out to the 1.5-2 inch you now.

225/60 on 14" on factory road wheels. I'm betting these are only 24-25" tall. A step up to a 15" wheel with a 27-28 inch tall tire will also create a 2 inch overall rise in ride height.

2. That appears to be the bumperette mounting strap. It should bolt into the frame in that area. If its loose, then either the bolt fell out or the captive frame nut broke and fell out.

3. You have the desireable 8.75 ring gear unit with a 489 center section. These rears are very stout and are good up to 600-700 horsepower with a few mods. Behind most street engines, these will live long and happy lives.

4. You can estimate this. Put rear in the air, turn one tire to verify if both tire rotate the same direction. If yes, then you have a sure grip in the housing (bonus!). Rotate the tire one revolution and count how many times driveshaft rotates. This will give you the ratio. If one tire rotates the opposite direct (opend diff, bummer), then put one tire on the ground and leave one tire up. Rotate the tire in the air one revolution and count the driveshaft rotations. This give you he ratio.

5.Overall height, this varies considerably based on tires aspect ratio. Generally speaking, it can be anywhere from below mid-sidewall to 1-2 inches over the top of the tire.
 
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cuda joe

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i agree with HPP 15 inch wheels work better with a 60 percent side wall tire ..i wouldn;t go with a larger rims and thin side walls it will be to bumpy of a ride
 
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tires1.Yes, in their installed position the leaf springs should be almost flat. They may have about 1.5-2" arch in them, max, when brand new. You can replace them, but you may not gain more than an inch or two of increased height, unless you current leafs are really, really fragged. You also don't mention how many leafs are in them. If you have the light duty 4 leaf version, then yeah, they are going to bottom out easily and you may want to get a set with a higher leaf count (the factory XHD would be good for this. But they aren't going to lift it 4 inches. If you buy leafs with 4-6 inch of free height, when installed they will flatten out to the 1.5-2 inch you now.

225/60 on 14" on factory road wheels. I'm betting these are only 24-25" tall. A step up to a 15" wheel with a 27-28 inch tall tire will also create a 2 inch overall rise in ride height.

2. That appears to be the bumperette mounting strap. It should bolt into the frame in that area. If its loose, then either the bolt fell out or the captive frame nut broke and fell out.

3. You have the desireable 8.75 ring gear unit with a 489 center section. These rears are very stout and are good up to 600-700 horsepower with a few mods. Behind most street engines, these will live long and happy lives.

4. You can estimate this. Put rear in the air, turn one tire to verify if both tire rotate the same direction. If yes, then you have a sure grip in the housing (bonus!). Rotate the tire one revolution and count how many times driveshaft rotates. This will give you the ratio. If one tire rotates the opposite direct (opend diff, bummer), then put one tire on the ground and leave one tire up. Rotate the tire in the air one revolution and count the driveshaft rotations. This give you he ratio.

5.Overall height, this varies considerably based on tires aspect ratio. Generally speaking, it can be anywhere from below mid-sidewall to 1-2 inches over the top of the tire.
I ordered replacement springs with a +1" rise, HD. I'll put them in and level the front up. See how that works and if that's not enough I'll try taller tires. from what I figure, the current tires are a little short, maybe 1/2" I've checked the speedo and when it's showing 60Mph, its really going 54 Mph. a shorter than normal tire would do that.
 

moparleo

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Remember that the tires height is divided by 2 when mounted to the axle.
1/2 is above the centerline of the axle and 1/2 is below.
And the tire squats under load. So a tire that measures 2" taller overall will raise the vehicle a little less than 1"
And as Chryco has said. the cars actually squatted in the rear when new and they never came with miss matched sizes from the factory.
The only cars that came that way were the AAR Cuda and the T/A Challenger. And that was for front of the wheel exhaust clearance.
 
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Remember that the tires height is divided by The

Remember that the tires height is divided by 2 when mounted to the axle.
1/2 is above the centerline of the axle and 1/2 is below.
And the tire squats under load. So a tire that measures 2" taller overall will raise the vehicle a little less than 1"
And as Chryco has said. the cars actually squatted in the rear when new and they never came with miss matched sizes from the factory.
The only cars that came that way were the AAR Cuda and the T/A Challenger. And that was for front of the wheel exhaust clearance.
I was working out the sidewall heigth when I determined they were about 1/2" short. According to the tire sheet I found in the glove box with the manual and other paperwork, the car had F70-14 on the front and F78-14 on the rear from the factory.
 
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