Rear shocks / struts

Yep, those are just Mickey Mouse overload springs that fit over the shocks. They are just a band aid for a good set of springs. I had a set of those on my 65 Dart and when I went over a set of railroad tracks at 55 mph, the coil caught the lip of the gas tank and peeled the tank out from under the car. It went sliding down the highway behind me. Lucky there was no fire. Contact Espo Springs and things and order yourself a new set. THey will last you a decade or more. Mine are 10 years old on my 66 and still hold the car up nicely.

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I may have misunderstood you, when you said you ordered a set from Espo Springs. Laura tells me you meant leaf springs, because they don't sell coil over springs for a dart or barracuda. I asked her for a quote on new leaf springs.
Thanks!