CrAzYMoPaRGuy, I don't suppose you have or could get pictures of the Plymouth with the 5th Ave suspension? If not could you get me contact info for the guy?

In my mind if I can't make the 605 Steering box conversion I'm trying to work out it might be an option to look at for my Plymouth.


I did a 5th Ave conversion on a 52 F1 pickup many years ago and happy with the results.

CrAzYMoPaRGuy, I don't suppose you have or could get pictures of the Plymouth with the 5th Ave suspension? If not could you get me contact info for the guy?

I did a 5th Ave conversion on a 52 F1 pickup many years ago and happy with the results.

Neat project, (love the color).


If interested I do have a spare pair of original V8 57-58 Dodge and Plymouth frame mounts. The round motor mounts the V8 cars used are still available, but the “cans” that go on the motor can be hard to find and are different than between the Poly/Hemi motors and the B/RB engines.


SANYO DIGITAL CAMERA by M Patterson, on Flickr


If using the original frame/suspension, you will need a 57-58 center sump pan and pickup is you use a Poly/first gen Hemi.




If you go B/RB and can’t find an early passenger car pan, a later B/RB pan will work if going the Big Block route, but it may need to be notched to clear the front crossmember.


I’ve done front disc brake conversions a couple of different ways on the 57-58s. 70’s A body Disc brakes were a popular swap 15 years ago (before their were kits using the original spindles). The spindles bolt on, but the tie rods and sleeves need to be shortened and the steering stop modified. I have also used late 70s C body brakes but that is even more work and requires modification to the spindles. I’m using an old AAJ disc brake conversion on my 57 Plymouth’s original spindles and am happy with it. I not sure if AAJ is still in business, but I think Scare Bird has a similar kit.


“…….If power steering is, or will be in play, do a Dakota clip……”

I absolutely agree with poorboy. If I was just starting to build my 57 Plymouth (or the old 440 powered 57 Coronet I used to have) now it would definitely be getting a later modle front frame clip.


The original steering boxes, both manual and especially power boxes suck on these cars. The way the box mounts and oil pan/torsion bar clearance issues make adapting something else (rack and pinion/modern steering box) very difficult is not impossible. I’m currently trying to adapt a 605 Saginaw box into my 57 Plymouth and if it is even possible, it’s going to be a lot of work.

In addition to the steering box issues, a couple of other shortcomings include:

The upper control arms are a 57-58 only item. They use very small control arm bushings that don’t like heavy engines (first gen Hemis or B/RB motor). Usually the bushings only last about 40-50K miles and are not pleasant to replace. They are also currently getting a little harder to find…..cost can run anywhere between $20 to$50 each (and you need 4).

The drag link is also a wear item due to having joints on the outer ends. You can still find these rebuilt, but they are not real cheap.

A word of advice on the on the steering gear. Regardless of the mileage on the gear send it out to be rebuilt before you install it. You sure don't want to have to pull it back out after you get the interior installed (The gear column and all have to be removed thru the floor into the passenger compartment.

As far as a PS pump there are 2 easy options as far as pump and bracket. One is the older TRW pump....as I recall the pressure is listed as being a little higher than the original pump but it will be fine.

The other option is using the newer brackets and a Saginaw pump. The majority of Saginaw pumps are made for the integral steering gear and has considerably higher pressure than the early Mopar gear is designed for. The trick is to spec a pump for a 70s Corvette with the slave cylinder power steering. Those pumps operate at a lower pressure and should work well with the early Mopar gear.

A couple of other things come to mind if you're using the original front suspension. 57-8 Chrysler Windsor torsion bars will fit under the 57-58 Dodge and Plymouths and are a bit more HD that the stock bars. Factory front sway bars are kind of rare on 57-58 Dodge and Plymouths. If you come across one they were standard on the 57-8 Imperials and will fit the Dodges and Plymouths (I suspect sway bars from Chryslers of that era will also fit). You will need to either cut off the frame brackets or fabricate some (I can send you pictures of the ones I built for my 57 Plymouth if you need them).

Nice score for sure

Kevin, not very good for two reasons.

1. The CV front track is too wide for most applications and uses a weird offset wheel.

2. The original poster appears to be very set on using some kind of early torsion bar suspension (I think).