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BrianInPa 04-24-2010 08:07 PM

Early '40's Plymouth independent suspension - any good?
I have a 1940 plymouth 4 door sedan, that is in good condition. I'm planning a "resto-rod" rebuild of this car. Basically, I want to upgrade the driveline and suspension / brakes. The engine will probably be a small block Chevy.

I'm having a hard time determining what to do with the front suspension. I've read in a couple places that these early Plymouth independent front ends are actually pretty good if they are rebuilt and the brakes and shocks are upgraded.

I've never driven one with upgraded brakes / shocks, so I was hoping someone could provide some feedback.

I'm just looking to build an occasional family cruiser. Keep in mind, I'm not taking this thing out on a road course.

Thanks for any input.

Brian 04-24-2010 09:00 PM

Chrysler products used the same system into the mid fifties. Well ahead of their time. All the parts are available. I have a 48 Dodge business coupe. All the front end parts purchased from vendor on Ebay. I then used a rebuilt Cavalier rack&pinion steering box. Also from an Ebay seller. Disc brake conversion. Stops great.

You have to re-position the shocks tho, they missed the boat on that.

Drives and steers very well. Nice and tight, not too quick. Decent road "Feel".

BrianInPa 04-25-2010 11:40 AM


I did find numerous kits for installing disc brakes on the Plymouth. I've also read about the shock relocation. However, I've never heard of installing the Cavalier rack & pinion. I'm very interested in that. Do you happen to have any photos of the steering mods?

Thanks again


48ChryslerRodder 04-25-2010 01:48 PM

I posted this and am passing this along. Just some info I have been given and shared about the Cavalier conversion. Hope this helps.

BrianInPa 04-26-2010 08:13 AM

Thanks for the info 48,
Can you post those photos here, or email them to me.
I registered on that site, but for some reason, it still blocks me from opening those photos.


Footstomper 04-26-2010 08:43 AM

41 Plymouth 4 door
I bought that sedan for 250. in 1979. It had the original green, I loved that car, I drove it for 5 years and swapped for a 48' ford 2 door sedan.
That plymouth was comfortable, response was tight and I never had to do anything to it. It was the best ride any car I had before, my wife thinks her Passat, she should have rode in that plymouth.

48ChryslerRodder 04-26-2010 04:47 PM

5 Attachment(s)
I have been looking for a power steering conversion and a member sent his setup with pictures to me. It is an install of a Cavalier power rack and pinion. The dimensions are close enough through the years that you could use this design. This was compiled by Kai Hendriksen from various sources. Follows;

Here are some Pics that I used to set up my power steering.
I lifted most from the forum. If I have offended anyone, I am truly sorry.

Below are the instructions from Fatman.
1. This kit is designed to fit late 30’s to early 50’s cars which have lower control arms whose inner shaft pivot line forms a “V” pointed toward the rear of the car (see diagram). Some of these cars use a bellcrank in the center to mount the tie rods, and some use a short LH and a long RH tie rod.
2. Before disassembling anything, put the car on jackstands on it’s frame, leveling the frame side to side and front to back. Then measure the height of the inner tie rod ends from the floor, and record that number. When the new rack & pinion is installed, it’s inner tie rod ends must maintain the same height as stock.
3. An 89-93 Cavalier rack & pinion is used in either manual or power versions along with it’s own inner and outer tie rod ends. Be sure to get the mount bushings and straps. We’ve supplied a Borgeson U-Joint to get you started with your steering hookup. Occasionally a Cavalier rack with a different spline shows up – don’t panic – just give us a call and we’ll exchange it for you! We also have u-joints to fit your steering column.
4. Replace the tie rod threaded connectors with the longer ones in the kit. Set the toe in at zero by turning the threaded adapters. The Cavalier outer tie rod end should fit your steering arms, and will usually require 1-3 flat washers to raise the nut up to the cotter key hole. If more than 3 washers are required, give us a call for a tapered tie rod hole sleeve.
5. Mount the rack with the brackets from the kit, and mock it up in place with a jack or wires tied to the frame rails. Be sure to maintain the height noted in #2 above, and be sure the rack is centered in it’s travel, as well as centered in the chassis. Also look out for oil pan interference and clearance for the tie rods as the suspension moves up and down and left to right.
6. Double check for any bumpsteer problems by checking for toe in change with suspension travel. Use a plumb bob at the outer end of the spindle, and mark the floor at full up and full down travel. If more than a 3/16” change is noted, try moving the outer tie rod ends down to see if it’s getting better or worse, and adjust accordingly
7. Now you can final trim the rack mounts to fit the frame contours. Some frames are wide enough as to require a small gusseted “shelf” added to the lower frame surface. We often find that motor mounts will be directly above these “shelves”, and can do double duty as both motor mounts and gussets. Add the kit gussets and weld everything securely in place.
8. Connect the rack and steering column with u-joints, being sure to keep them properly phased. Connect the hoses next, being sure not to confuse the pressure and return ports. Use genuine GM Power Steering Fluid. If the effort is too light, you can reduce the pump’s output pressure by shortening the pressure relief valve spring inside the pressure line fitting in the pump body. It’s about the size of your little finger-try cutting off ¼ of the length for starters.
I will post the rest next.

48ChryslerRodder 04-26-2010 04:49 PM

3 Attachment(s)
Here is the rest of the info. I apologize for not have the pictures in between the relevant text sections. The pictures are numbered in the order that they were in the document file. If any one would like this sent to them it is 1.5 meg abytes and will be a very long down load on dial up. Just drop me a PM and I will send it to you. Many thanks to Kai for sharing this with me and I hope he doesn't mind my passing this along.
The above adaptor I made.
Cut 3 ½ inches off the right hand thread end of the tri-rods.
Drill and tap; the cut off end (leaving the original right hand threads intact) to metric 18 X 1.5 to accept the original Cavalier adjusting screw. This make an adjusting device of left hand for the Cavalier tie rod and the right hand tie rod end original from the MoPar. I cut about an inch off the end of the tie rod end to allow enough of the thing to fit in the end. Tack weld the Cavalier adjusting sleeve to the 3 ½ cut off piece.

The adapter plates are made from ¼ in plate and 1” square tubing. The tubing is offset to allow the rubber to fit.
The above has the special Fatman adapter and Datson tie rod ends.
This is my tie rod end and adapter installed
The below pics are what I patterned my modification of the steering shaft after cutting off the steering box with a “sawzall”
This is the power steering pump mount I used from Ugly Truckling, here id the website. It has the instructions when you go to this site.

The hoses I made from 3/8 braided hose. You can have them made at any shop that makes hoses for tractors and the like. I would suggest that when you get the rack make sure you get the hoses too.

From the junkyard you need the total rack and pinion steering,(tie rods, hoses, adjusting sleeves, and the mounting brackets)

48ChryslerRodder 04-26-2010 04:52 PM

Hope this helps you. Just passing along knowledge that was shared with me. Many thanks to Kai who put this info together. :thumbup:

BrianInPa 04-30-2010 08:27 PM

Thanks for all of the info 48CR.
That Cavalier rack makes a nice, clean swap.
What engine are you running in your 48?

48ChryslerRodder 05-02-2010 12:02 PM

I am going to install a 305/700r4. I know it is not popular but I am thinking economy. I am going for a resto rod look. I want to upgrade the brakes, drive train and make it a safe cruiser.

BrianInPa 05-02-2010 01:46 PM

Sounds like you're on exactly the same path as me.
My car is basically a resto-rod as well.
I have a 1991 caprice wagon with a 305 that is soon going to donate its motor and tranny to the '40 Plymouth.
Maybe we should swap "in progress" photos at some point. Unfortunately, I'm just in the beginning stages of my project.

48ChryslerRodder 05-03-2010 08:54 AM

Mine is a long term project. I have been collecting parts and ideas for the last 10 years. I am getting my garage in shape so I can work out there without having to half empty it to work. Every time I do I get people stopping by for my "garage sale" that is not. I found someone over on the HAMB site that makes weld in motor mounts for sbc's that look really nice and can be cut to fit. I have been collecting info and pictures from the web for a while so I have info on a variety of ways to do things on these cars. Send me a pm sometime and we can share ideas. :thumbup:

48ChryslerRodder 05-03-2010 09:00 AM

I also have some good info on a couple of ways to do the front shock relocation. :thumbup: 03-15-2013 10:12 AM

1948 chrysler cruiser
Hey guy..I also own a 1948 New Yorker...I took out the inline 8 and installed a SBC 400 cu. in. engine w/TH350....all this was done last summer working solo...haven't gotten it running yet, but it should go this summer...I like the idea of a Cavalier rack, but that will be after it gets driven for a while...have to install the aluminum radiator and fire it up for the first time....I also have a 1940 Plymouth P10 business coupe....that will be getting a beam axle and a v8 of some yet to be determined make....I like reading about your projects...just had to jump in and say something...good luck and keep posting....Mike S.:thumbup:

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