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Old 08-24-2018, 06:22 PM
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How to figure proper shock size

I have picked up a 1948 Plymouth hot rod with a after market rack pinion of unknown vintage. No sway bar. A lot of roll when driving. Does anyone know how to determine the replacement shocks needed to tighten up the front? Proper size?

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Old 08-24-2018, 06:40 PM
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Shocks do not counter roll, they just prevent the suspension from going "bouncy bounce" uncontrollably with each dip or bump in the road.

To reduce roll, you either have to increase spring rate(install different front springs).or add a anti-sway bar(anti-roll bar).

The anti-roll bar is the smart move.

As far as new shocks, you didn't say what suspension is being used...you mentioned and aftermarket steering rack, but that has nothing to do with shocks or suspension.
Is it still a stock suspension, with just the steering rack retro-fit?
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Old 08-24-2018, 06:45 PM
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Eric was posting while I was still typing.....

Describe the type of front suspension on the car. Is it stock like this?
https://www.jalopyjournal.com/forum/...-coupe.125109/
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Old 08-25-2018, 07:02 AM
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You may not need shocks, but you sure do need an anti-sway bar! Go big! This will seriously reduce roll and make the car much more pleasant to drive.
After that, you may indeed find you need shocks. You will need to measure your current shock length at ride height (car sitting normally on its wheels), fully extended (wheel hanging) and compressed (that is harder to do...). Then you can go to the site of a shock manufacturer (and look the list of their product with lengths, mounting styles... (Monroe has such a list online, very convenient!) and find the shock that will (should!) fit. With these shock dimensions, you can also see with an aftermarket shock manufacturer, if you want something fancy.
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Old 08-25-2018, 09:13 AM
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I agree that I need a sway bar. I have been attempting to identify the rack and pinion that was installed to see if that would give me options. I can make measurements of various mounting points on the frame. I do not have any holes on the tubular a-arms for a sway bar mount. Could I extend off the bottom shock mount?
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Old 08-25-2018, 09:15 AM
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The a-arms are part of the rack and pinion front clip so they are not original. However, there still is a spring and shock not a coilover.
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Old 08-25-2018, 09:21 AM
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Picture will help.. to install a swaybar would require fabrication so how are your fabrication skills or do you know someone that can help you? There are a lot of options that may work just which one will depend on the current layout of the front end..

Sam
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I have tried most all of it and now do what is known to work..
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Old 08-25-2018, 09:28 AM
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Shocks

Adding a sway bar can be tricky because everything is in the way. For a front sway bar the usual mounts are the frame rails forward of the front end. This gets the bar away from steering, engine, etc. The ends of the sway bar will be hooked to a vertical link which is connected to the lower A arm somehow. Big question is where to get a sway bar of the right length? You can go to the junk yard armed with your measurements and start looking. This is tuff because they are normally setting on the ground or close to it and most sway bars have a bunch of bends rather than just bent at the ends. Second is to look on line and third is to go to the WELD IT series. They have a nice one that you can cut to length.
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Old 08-25-2018, 02:38 PM
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Yes picture will help.

A option that will work is to head to the scrap yard and see if you can wrestle up some steel rod.

Couple common bushings from a truck in a junk yard, a torch, and a welder to weld the ends and you can build a "custom" sway bar that is built to match your application.

Yes I am cheap, no it is not bolt in, This will work better then something that is "almost" a correct fit.




As far as the springs goes. You may be able to fit coil over "load carrrier" shocks in place of your current ones which will give you an additional spring. This is a "helper spring" and helps with old worn coil/leaf springs and they do lessen roll.

You have a non stock application which means you need to break out the tape measure and check extended and closed(compressed) lengths of your current springs. Then check the area around the springs to see if you have enough room as the coils add some diameter to the springs. Nothing a new longer shock mount can't fix.

They are mainly used in trucks. But they are also made as a direct replacement for big boats of the 70's and that application is probably what you will end up using.

They come in a wide variety of lengths. Once you know your measurments a email or some searching can get you something that will bolt in or require minor modification.

https://www.summitracing.com/parts/g.../make/cadillac

https://www.summitracing.com/parts/g...iABEgIZc_D_BwE

THE SHOCKS ABOVE DO NOT INCREASE FRONT END CAPACITY. They are just a good cheap "double action" quality shock that I have used on 2wd trucks, 2wd boats, and some mild 4wd's as a direct shock replacement and never had an issue with quality or cost.
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Old 08-31-2018, 11:50 AM
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for the shocks: first determine the length of shock needed. from fully jacked up to suspension fully compressed. i downloaded the monroe catalog, determined what ends i needed and looked for a shock that fit the application

http://www.monroe.com/downloads/inst...ifications.pdf

sway bar: i bought an 86 trans am rearend for my 58 truk that came with a sway bar. the ends were turned in and hit my leaf springs. i heated them cherry red and bent them out. what i'm saying is get something to fit the frame and is close to what you need, then move the eyes in or out to fit your application
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Old 09-01-2018, 10:08 AM
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So it looks like- sway bar first, shocks second. I will post pics of front end asap. Thanks to all!!
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Old 09-01-2018, 04:51 PM
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There’s another option you may want to think about. Redesigning the front upper control arms and adding anti-dive.
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