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55 Plymouth Savoy M body front suspension swap

Posted By: 72Swinger

55 Plymouth Savoy M body front suspension swap - 06/20/17 05:14 PM

Anyone done a FMJ swap to one of these cars? Have a line on both and it looks like track width wise I should be good but may need to change front rails. What others done and where are some links? Roadster shop has done one but they left the rear rails stock width with pizza cutters on the back. I plan to minitub this one and back half it to.
Posted By: Old Ray

Re: 55 Plymouth Savoy M body front suspension swap - 06/20/17 09:36 PM

Dakota on the front seems to be a popular sub-frame transplant, I will let you know in a couple of weeks, work is in progress on a '56 Plymouth (canadian Dodge) There are some posts on this site showing other projects with Dakota.
Posted By: poorboy

Re: 55 Plymouth Savoy M body front suspension swap - 06/21/17 04:50 AM

I've not done an FMJ clip on a car before, but I have installed a few under trucks. The FMJ crossmember will require new frame rails. The mounting bolts are wider at the front then they are at the back, so you end up building a tube frame (1/8" wall 2" x 3" tube) with notches to clear the crossmember.

On 50s Dodge trucks, the frame rear sections are usually welded about 1 1/2" down inside your existing frame, then the front section is welded outside the rear sections. You have to notch the rear section so the rubber mount fits up inside the 2' x 3" tube so the bottom is neatly flush. The rubber bushings at the front sit under the tube. Then you need to box everything in. After that, you get to figure out how to mount your radiator support and support your front sheet metal.

When you get all done, you will have an antiquated front suspension that is long and heavy ahead of the front wheels with a steering box sitting side of your motor. The FMJ clip was a compromised suspension system when it was designed, and still maintains less the desirable suspension geometry.

A 1st or 2nd Gen Dakota (1988 - 1990 or 1991 to 1996) are a simple modern suspension system that was new whit the truck's design. 1st gen had 5 bolt wheels with a 4 1/2" bolt pattern. The 2nd Gen has 6 bolt wheels that can be converter to 5 bolt simply by replacing the 6 bot rotors with the 5 bolt rotors. The 3rd gen has 6 bolt wheels but parts are not interchangeable with the older parts.
The Dakota has a 34" outside dimension boxed frame back to the trans crossmember with the suspension parts attached to it. The trick these days it to find a frame that is affordable and not rusty. Gene
Posted By: dynamite

Re: 55 Plymouth Savoy M body front suspension swap - 06/22/17 02:55 PM

Yes I did the FMJ front end clip on my 56 Plymouth....about 10 years ago..for me it was an easy swap.. and would have been easier if I ran a small block..,, but I first put in a 440 and yes the steering box and headers both wanted to share the same space..I bought a complete 1986 Chrysler 5 th ave.. and used a lot of the parts. steering column , dome light and just everything I could.. ..but other than the exhaust I have had no problems.. I have driven it from Florida to NJ , round trip twice.. and enjoyed the ride and attention..I'm sure there are more modern swaps.. but I now have a 493 stroker motor in it and enjoy the 11.38 1/4 mile times .I just pulled the 493 and am installing a complete stock 361 BB and have planned some nice longer cruises this summer..I had a lot of pics of the install, but when my PC crashed I lost everything.. I'll try to send what I have..It has a nice ride and have no problems going thru the lights at 120 mph..Yes today I might have choosen a more modern front end but I'm happy... Good luck..

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Posted By: CrAzYMoPaRGuY

Re: 55 Plymouth Savoy M body front suspension swap - 06/27/17 12:23 AM

I looked at a 56 Dodge for sale locally that had a Fifth Ave clip in it, the front frame rails were spliced in. Well done job and everything fit, it sat low and it was hard to tell it was altered at first look!!! Track width was good too.....
Posted By: dynamite

Re: 55 Plymouth Savoy M body front suspension swap - 06/27/17 02:27 PM

CRAZYMOPARGUY IS CORRECT .. THE FMJ FRONT CLIP FITS NICELY .. AND EVEN IF YOU USE A R/B MOTOR LIKE I DID, THE STOCK EXHAUST MANIFOLDS WILL WORK JUST FINE.I USED THEM AT FIRST AND A LOCAL MUFFLER SHOP MADE THE EXHAUST PIPES.. LATER.I CHOSE TO RUN HEADERS AND THEY WON'T CLEAR THE P/S BOX WITHOUT MAJOR CUSS WORDS.. I HAD TO USE WHEEL SPACERS TO GET THE FRONT WHEELS TO MATCH THE REAR I THINK IT WAS BECAUSE OF MY CHOICE OF THE CUSTOM WHEELS I USED..I HAVE PUT MILES ON THIS SWAP AND HAVEN'T HAD A PROBLEM..I AM AN OLD MOPAR TECH AND I GOT MYSELF 3 DIFFERENT MOTORS ..THE 493 WAS A BLAST..BUT TOO MUCH FOR CRUISING,I STILL HAVE A MILD 440 ALSO, BUT I JUST INSTALLED A SMALL BIG BLOCK.. 361 CID ,AND IN MY OLD AGE I'M JUST GOING TO CRUISE..I MAY SELL OR PART OUT THE 493 IT'S A PERFECT ROLLER CAM ALUM HEAD STRONG RUNNING MOTOR....I'LL KEEP THE 440..
Posted By: Old Ray

Re: 55 Plymouth Savoy M body front suspension swap - 06/27/17 05:35 PM

Why are you shouting ? smile

Using a Dakota with rack and pinion steering there is no steering box!
Posted By: dynamite

Re: 55 Plymouth Savoy M body front suspension swap - 06/27/17 05:52 PM

Sorry Old Ray,, didn't mean to shout...the rack and pinion is probaly a much better way to go.....He just asked if anyone has done a FMJ install so I answered the post..yup I did.. today I may go another way ..thats all..At the time it was a very cheap job for me..I bought the 86 5 th ave for $ 250.00 in great condition but badly over heated motor..took everything I needed and sold the car for $ 200.00.Got the k frame.with a fresh disc brake job ,and new shocks.. master cylinder and anything else I wanted..including the tilt wheel steering column, and all the power steering stuff..
Posted By: poorboy

Re: 55 Plymouth Savoy M body front suspension swap - 06/28/17 04:55 AM

Getting a Dakota rack to fit on that k member would be a major pita, it would need to sit the same place as both the torsion bars now occupy.

The FMJ clip was a cheap way to get independent suspension and disc brakes on old trucks, I did a few of them. Nice ride, track straight, good brakes. They worked well unless you liked to corner hard, or needed to raise up the front end. The cross bars were a bit soft and wouldn't hold a lifted car/truck very long.

I wouldn't do one these days. In fact, I scrapped a complete crossmember a few years ago because I was tired of tripping over it.

I like the 87-96 Dakota frames, but now its getting hard to find them that don't have rust issues around here. Gene
Posted By: Supercuda

Re: 55 Plymouth Savoy M body front suspension swap - 06/28/17 02:28 PM

Not sure why someone would want to take a rear steer setup and totally waste the geometry by putting a front steer rack in it.

Be smarter to use a rear steer rack.
Posted By: Old Ray

Re: 55 Plymouth Savoy M body front suspension swap - 06/28/17 03:48 PM

Originally Posted By Old Ray
Using a Dakota with rack and pinion steering there is no steering box!


Seems to be some misunderstanding here.To clarify;

Using a Dakota (sub-frame) with rack and pinion steering there is no steering box!

smile
Posted By: dogdays

Re: 55 Plymouth Savoy M body front suspension swap - 06/28/17 10:49 PM

The transverse torsion bar front end has a big problem with suspension geometry.

I have a friend who bought a mid '50s ford pickup with one, and it seems to have been installed wrong. The truck was actually dangerous to drive. It required a lot of dedication from a front end shop to get it so it felt safe on the highway.

The Dakota front end is a much better design, technically. Shoot, the '55 front end is probably better. As disk brake kits and rebuild parts are available, why swap at all? Even dropped spindles can be found.

R.
Posted By: Supercuda

Re: 55 Plymouth Savoy M body front suspension swap - 06/29/17 12:10 AM

I put over 200k miles on my 87 Diplomat with no geometry issues. Can't blame the suspension for a bad install.
Posted By: dynamite

Re: 55 Plymouth Savoy M body front suspension swap - 06/29/17 02:00 AM

I agree ,,I have drivin my 56 with the fmj k frame for 10 years,, 2 round trips from FL to NJ at interstate speeds with no problems..dozens of 1/4 mile passes over 118 mph...120 mph went straight and sweet.The factory disc brakes were fine.

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Posted By: CrAzYMoPaRGuY

Re: 55 Plymouth Savoy M body front suspension swap - 06/30/17 12:48 AM

Originally Posted By dogdays
The transverse torsion bar front end has a big problem with suspension geometry.

I have a friend who bought a mid '50s ford pickup with one, and it seems to have been installed wrong. The truck was actually dangerous to drive. It required a lot of dedication from a front end shop to get it so it felt safe on the highway.

The Dakota front end is a much better design, technically. Shoot, the '55 front end is probably better. As disk brake kits and rebuild parts are available, why swap at all? Even dropped spindles can be found.

R.


Your friend might have problems but the FMJ front ends don't. I've driven lots of them.
Posted By: poorboy

Re: 55 Plymouth Savoy M body front suspension swap - 06/30/17 03:57 AM

Originally Posted By CrAzYMoPaRGuY
Originally Posted By dogdays
The transverse torsion bar front end has a big problem with suspension geometry.

I have a friend who bought a mid '50s ford pickup with one, and it seems to have been installed wrong. The truck was actually dangerous to drive. It required a lot of dedication from a front end shop to get it so it felt safe on the highway.

The Dakota front end is a much better design, technically. Shoot, the '55 front end is probably better. As disk brake kits and rebuild parts are available, why swap at all? Even dropped spindles can be found.

R.


Your friend might have problems but the FMJ front ends don't. I've driven lots of them.


I agree, I have installed 4 of the FMJ crossmembers myself and all worked very well, can't blame the parts for a poor install job.
That said, I do like the Dakota much better. Gene
Posted By: CrAzYMoPaRGuY

Re: 55 Plymouth Savoy M body front suspension swap - 06/30/17 11:55 PM

Originally Posted By poorboy
Originally Posted By CrAzYMoPaRGuY
Originally Posted By dogdays
The transverse torsion bar front end has a big problem with suspension geometry.

I have a friend who bought a mid '50s ford pickup with one, and it seems to have been installed wrong. The truck was actually dangerous to drive. It required a lot of dedication from a front end shop to get it so it felt safe on the highway.

The Dakota front end is a much better design, technically. Shoot, the '55 front end is probably better. As disk brake kits and rebuild parts are available, why swap at all? Even dropped spindles can be found.

R.


Your friend might have problems but the FMJ front ends don't. I've driven lots of them.


I agree, I have installed 4 of the FMJ crossmembers myself and all worked very well, can't blame the parts for a poor install job.
That said, I do like the Dakota much better. Gene



I'm trying a Dakota out for the first time. I've got my 60 D100 ready for some newness.....
Posted By: Twostick

Re: 55 Plymouth Savoy M body front suspension swap - 07/10/17 03:43 AM

The FMJ has geometry issues from a performance driving standpoint ie road racing etc. Daily driving chores not so much.

Kevin
Posted By: Supercuda

Re: 55 Plymouth Savoy M body front suspension swap - 07/10/17 04:12 AM

Originally Posted By Twostick
The FMJ has geometry issues from a performance driving standpoint ie road racing etc. Daily driving chores not so much.

Kevin


That would be a different forum and thousands of cop cars tell me the FMJ suspension is just fine for 99% of what anyone will do with it. If you are the 1% then I doubt any 100% stock setup will suffice.
Posted By: Greg55_99

Re: 55 Plymouth Savoy M body front suspension swap - 07/17/17 06:52 PM

I just let this go for $150. As has been stated, it's just fine for most driving. I just didn't need it anymore.

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