Need advice for new rear leafs, stock height to match 1.03 bars.

Discussion in 'Suspension, Steering and Chassis' started by 340doc, Jun 11, 2018.

  1. 340doc

    340doc Well-Known Member

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    Looking to replace the mushy stock 5 leaf springs, on my son's 70 Dart. We just upgraded to 17" rims and good tires and the soft springs really show up now. Looking for stock height and a rate to match 1.03 front bars. Can't wait to put on a better set!

    IMG_20180611_183342.jpg
     
  2. 66FormulaS273

    66FormulaS273 FABO Gold Member FABO Gold Member

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  3. Lee Robinson

    Lee Robinson FABO Gold Member FABO Gold Member

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    • Thanks! Thanks! x 1
    • 72bluNblu

      72bluNblu FABO Gold Member FABO Gold Member

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      Looks great already! :thumbsup:

      ESPO is probably your best bet, a set of XHD's with the stock arch should be the ticket.

      The factory spring rate wasn't as far off in the back as it was in the front. The XHD's should be ~110 lb/in, most of the road handling springs are set up to be in the 120- 130 lb/in range. Peter Bergman has a set of springs that he sells at Bergman AutoCraft that are custom spec'd and made by Eaton, that's a 130 lb/in spring. I run the discontinued AFCO 121 lb/in springs on my Duster, and they actually work pretty well with a rear sway bar and the 1.12" torsion bars I run up front. The Mopar Performance Oval Track springs that are being sold again are also 120 lb/in, but they're being made in Mexico so the quality may not be what it was when AFCO was making them. I have a set of the oval track springs but I haven't run them yet.
       
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      • 340doc

        340doc Well-Known Member

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      • 340doc

        340doc Well-Known Member

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        Thanks Lee
         
      • 340doc

        340doc Well-Known Member

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        Thanks blu, we're happy with the height of the car and hoping new stock height springs wont be too far off, compared to the old soft springs. We have the adjustable front hangers on stock hole now, so we got a little wiggle room.
         
      • tanis4457

        tanis4457 Well-Known Member

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        • Johnny Dart

          Johnny Dart Well-Known Member

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          Get a set of stock replacement springs from ESPO. They will raise the back of the car, compared to the 50yr old springs you have now. Use the other hole on the adjustable hanger, which drops it 1" I believe ?
          Good to go.
           
        • 340doc

          340doc Well-Known Member

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          Thanks Johnny D. I'm worried how much it will raise it, hopefully not too much. I'm reluctant to get a lower spring than stock, its easier to drop the back than raise it.
           
        • 340doc

          340doc Well-Known Member

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          Is this a lower spring than stock?
           
        • dgibby

          dgibby Well-Known Member

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          Call or do the online chat with ESPO. They can build the stock spring with a - 1 or -2 inch drop to keep the look that you want.
           
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

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          They’re not shorter. The front section of the spring is slightly longer, so if you use them with stock hangers it moves the axle back about a 1/2”. Probably a little less. If you read the description on the link you’ll see it says the hangers are shorter, not the springs.

          It allows for a taller tire, and does the same thing all the drag race guys do when they shim their hangers back.

          The zero arch spring is about the same height as stock. Maybe slightly lower, but not much.

          Those have the same arch as my AFCO speings. I’m actually pretty sure it’s the same spring, just made by MP. But they’re made in Mexico. I run the Mopar XHD’s that also made in Mexico on my Challenger. They’re fine, but they sagged quite a bit after install.
           
        • ir3333

          ir3333 Well-Known Member

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          i have used the oval track springs and if i remember correctly the front half is 1/2" shorter so the extended front mounts were required.They were made in Mexico and both had grinder marks were they were tested for hardness.I was impressed with the ride.
          I also have used the espo stock 6 leaf springs. I think they sent me 1" over because the dart sat too high for my liking so I made new front spring mounts to lower the rear to stock height.The ride is good.
           
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

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          No. The oval track springs have a LONGER front section. By a 1/2”. The special hanger is shorter, not the spring. Just look at the link for the special AR hangers, which says the hangers are shorter by a 1/2”.

          And regardless, they work just fine with a standard hanger, because the axle wasn’t centered in the wheel opening from the factory.
           
        • ir3333

          ir3333 Well-Known Member

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        • tanis4457

          tanis4457 Well-Known Member

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          Oops my bad thanks for the correction
           
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

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          No worries, I have to check myself all the time when I just go off the top of my head.

          But yeah, the front section is a 1/2" longer than stock. That doesn't necessarily mean you need different hangers though. I use mine with stock hangers, and the result on most A-bodies should be a wheel that is closer to centered in the wheel opening than it was from the factory. You can see that on my Duster, this is it below with the AFCO 121 lb/in springs. They're the same dimensions as the Mopar Oval Tracks. I'm actually pretty sure they're the same springs, just made by AFCO instead of MP, as they were discontinued by AFCO at the same exact same time the MP oval tracks went back into production, and the AFCO springs with different spring rates are still available.

          At any rate, you don't need the special hangers to run them, and most people will actually benefit from not using the special hangers as it will center the wheel. You should check your driveshaft engagement, but in most cases it should be ok.
          IMG_2484a_zpscao5szar.jpg