Opinions wanted for replacement Rear Spring selection. Thank you

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Cubzy

Cubzy

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Hi All, I just purchased this 1970 Dart Swinger 340 4 Speed. It’s got saggy original springs and clapped out air shocks. I plan to replace the springs and install Monroe oil/gas filled shocks. I’m the weekend warrior that takes the car out a drives it for recreation. No racetrack or aggressive pulls with the exception of occasional burnout. My question is which Spring should I purchase?

I have easy access to Mopar SuperStock Springs.
P4120863/4120864 2800lbs
P3412002/3412003 3200lbs
My friend recently installed a set of the 3200lb springs and now his car is very high in the back. Much more than factory. I’m looking for opinions whether the 2800lb springs would allow rear to sit lower than the 3200lb springs? Assuming maybe lower than the 3200lbs but higher than the factory stock height. Perhaps there is a different spring that is available that people can suggest for a factory ride height/clearance. I’ll post couple pictures of the car. Thanks in advance.
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You don't need SS springs. Contact ESPO Springs and Things and tell them what you have and want. I hear they are busy and backlogged but it will be worth the wait. Oh I see you are from Canada. That may change options.
 
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Being in Canada may preclude some vendors because of shipping. I got springs for my swinger from some place in Michigan, John R Spring Service.

2800 would ride smoother. We used the 2800 on 4 speed drag cars. 3200 gonna be stiff.

I don't recall the ride height difference in the two, I suspect the 3200 would ride higher and then you have the pass side higher than drivers side bias when using SS springs. On streeters I used to put two left or two rt side springs on cars so they sit level.
 
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I’ve been wondering the difference between the two as well. You should try the 2800lb ones, buy two left side springs then the car will sit level. (Super stock springs will have the right side sit higher than the left if you buy the pair as listed) Then PLEASE POST BEFORE AND AFTER PICTURES! I’ll be forever grateful. Where in bc are you? I’m your neighbour on the other side of the Rockies.

Nice car btw…
 
Cubzy said:
I’m the weekend warrior that takes the car out a drives it for recreation. No racetrack or aggressive pulls with the exception of occasional burnout.
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for that intended us stay away from SS springs...

for your use i'd call espo ( https://www.springsnthings.com/ ) and get a set of 6 leaf V8 springs in whatever flavor you desire. stock height, +1" and +2". ( +1" is th emost i'd go) you'll be much happier with them in my opinion...

the springs are not always on their site. give them a call. the woman that usually answers the phone os very knowlegeable..


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ESPO +1" Springs... Torque ubolts to 45ft-lb...... that was a hard lesson learned...
 
I will post a photo of my 70. The previous owner added a single leaf to the stock springs. I think it ame from a pick up because it is quite thick. It did raise the rear but it does ride pretty solid. Not bad just pretty stiff. I would all it a 1" over stock. (at least) You can see how much tire is showing with a 255/60-15 on 15x7 wheels.

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JDMopar said:
John R Spring is supposedly the supplier for ESPO. :thumbsup:

John R. Spring Service, Inc. | Spring Manufacturer

We carry a full line of Leaf Springs, Coil Springs and Accessories for passenger cars, light trucks, heavy trucks and trailers, Western Plow parts, Load Master Helper Springs and Load Star Variable Rate Coil Springs
www.johnrspring.com
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figures...they are 5 miles from me... didn't know
 
Us cranky old guys know some things on occasion. LOL

It's been a while but I pulled that one out of the noggin. If the OP is close to Detroit, might be worth a jaunt over the border to get a set.

Got as soft spot for yellow 340 Swingers.

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No matter what springs you use, remember, you can always get them arched or de-arched
 
How do Eaton springs compare to ESPO's price wise? Just curious.

I put some ESPO coil springs on the front of my 49 Dodge and the front sat too high until I cut one coil off each side. Have Eaton heavy duty leaf springs on the rear of my 59 Dodge and 56 Plymouth. Eaton's springs look good and the cars sit just where I wanted them to. But they are not cheap.

Eaton claims they were an OEM supplier and have factory blueprints for the springs they sell. Have no idea if that's true or not.
 
So you’re the buyer of that Swinger!

As others have said, no need for SS springs if it’s going to be a cruiser. Your teeth will rattle.

Give your local Chrysler parts department a call to see if they can order in some XHD springs for you. That’s what I did but it was over 10 years ago. Didn’t need to pay for shipping. Chrysler sourced them from JR Spring as their name was sprayed on them.
 
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65 Cuda 340 said:
How do Eaton springs compare to ESPO's price wise? Just curious.

I put some ESPO coil springs on the front of my 49 Dodge and the front sat too high until I cut one coil off each side. Have Eaton heavy duty leaf springs on the rear of my 59 Dodge and 56 Plymouth. Eaton's springs look good and the cars sit just where I wanted them to. But they are not cheap.

Eaton claims they were an OEM supplier and have factory blueprints for the springs they sell. Have no idea if that's true or not.
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eaton is a great spring. lil more pricey then the espo.. i have a big block dart stock height eaton on the rear of our dart.. tires are a 225/60-15 for reference

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General Springs is another supplier. I bought a set of theirs but can't offer any follow-up, they have not been installed yet.
 
I can take a pic of mine tonight with espo +1's if you want... i fit 30" tires in with them and it doesn't sit like a stinkbug like SS springs...
 
Actually.. OP hasn't been around so no point :)

Soo.. um.... what do you guys think bout 318s? Everyone prefers them over 360s right?
 
I've used both ESPO and General springs. I got ESPO (A body 383 springs) for my 70 Duster and it sat about an inch higher than stock. Laura was good to work with. I used General springs for my 72 Challenger because the ESPO springs were +1 higher and I wanted stock height. I got the HD 440 springs for the Challenger. A bit stiffer but rides much better than the weak 4 leaf springs that were on there. I also upgraded to the Bilstein shocks which tamed the ride a bit as well. Don't think you'll go wrong with either ESPO or General.
 
You could also re-arch what you have if they are in good condition otherwise. I've re-arched jeep springs with a hydraulic press but it takes time and care. You could also add a leaf for more rate or half a leaf (cut off behind the axle with a plasma torch) for a traction aid with different clamps for the thicker stack. Most older vehicles have 2.5" wide leafs but center hole size varies. I think the Mancini XHD set would be hard to beat off the shelf for $325. If you can get the SS for little to nothing, you might pull a leaf from the middle to soften them up and drop the car a little if needed. The longer leafs are softer.
 
Super stock springs were designed for drag cars, not street cars and are (IMHO) inappropriate for that use. One spring is much stiffer than the other and often even makes the car sit tilted. Works well to launch a leaf spring drag car straight and flat, but driving on the street... not so great.
 
I’m leaning hard towards the P4120864/P4120863 2800lb springs presently(lighter of the two SS springs). Can the Dart owners with SS springs post pictures of their car with height for reference. Especially the Darts as they have a much lower quarter panel wheel opening. Makes it easier to reference what my car will look like. Also if you can mention if you have 2800lb. or 3200lb. springs. What else will I need to purchase to complete the job. Front bushing are included. Will I need to upsize the front and rear hangar bolt hole and bolt size to 5/8 inch? CAn I purchase the larger size bushing kit? Do I need to purchase shackles or just reuse existing ones? Will I also need longer shocks with SS leafs? I hear KYB are good to use. Or will Monroe shocks still work? Thanks
 
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Icetech said:
Actually.. OP hasn't been around so no point :)

Soo.. um.... what do you guys think bout 318s? Everyone prefers them over 360s right?
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Hell yeah, the smaller bore pulls the air in faster making better cylinder fill. so even tho smaller displacement, I've heard they make the same horsepower. put a 340 air cleaner on & theyll think thats why you kicked their ***.
 
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