Are suspension parts differernt for a V-8 K frame and the slant 6 K frame?

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myasylum

myasylum

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My Duster is getting down right scary on the freeway!

Then i realized this same suspension was holding a slant 6 for 38 years of its life and is now carrying a 360.

Now... I just kept the /6 K frame and used the V-8 adapter. When I look for a suspension kit, should I be looking for a /6 suspension kit if thats all that is going to fit due to the K frame?

If it's all the same, what is suggested I get? A performance kit of some kind?

I found this one...

http://www.justsuspension.com/mopar-a-body-front-end-kit-73-76-disc.html

or then there is this one that cost more...

http://www.p-s-t.com/s.nl/it.A/id.170/.f?sc=12

Thanks Much!
 
For a disk brake car those kits are identical for a /6 or V8 car. All the bushings and ball joints are the same from /6 to V8, the only difference in the front rebuild kits is because of the type of brakes, which vary by year. As far as which kit to get, it looks like the PST kit is more because it includes an idler arm, cam bolts, and sway bar end links.

If you switched to a V8 though you should upgrade your torsion bars, which are different for a /6. Get a nice set of 1" bars from Just Suspension, Firm Feel or PST. The /6 bars are ridiculously soft, upgrading the bars will give you a much better handling car. But other than the torsion bars, everything else is the same.

I would also suggest getting a set of offset upper control arm bushings, Moog 7103. The offset bushings allow you to set the alignment of the car for modern radial tires, ie, with more + caster. Below is an alignment guide and the install instructions for the Moog 7103's, which is different than the "stock" instructions that come with them.
 

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Did you change the slant 6 torsion bars out for V8 bars when you swapped engines? If not now is the time to change them to .920 or larger bars.
 
Thanks dude!

Excellent post!

I think the control arm bushings come with the kit?!

I did hear the front sway bar (If I chose to go that route? ) are different depending on the K Frame. Is that part true?

Thanks!

Oh, I never changed the bars. Its been like this for 3 years. Maybe that's the whole problem?:banghead:
 
myasylum said:
My Duster is getting down right scary on the freeway!............ I never changed the bars. Its been like this for 3 years. ......
Click to expand...

So did it used to drive OK, and got worse, or has it been scary for 3 years? Which is it?

Because.............

1----If it's "getting scary" that is, it used to drive fair, but got worse, something has changed, broken, worn, and IT IS NOT T bars, although T bars would certainly improve handling

3----On the other had if it's "been scary" for all 3 years, and has pretty much stayed that way, almost anything is possible.

But the COMPLETE answer is to suspect EVERYTHING. And check everything. If you have never rebuilt the front end, I would just ASSUME that a 30-50 year old car has worn out the front end.

But this does not discount the possibility that something has BROKEN such as the LCA anchors in the K member, etc.

On top of everything else, TIRES can cause a car to drive unbelieveably evil, and don't leave out the REAR suspension---something loose/ broken back there

Get the car jacked up under the LCA so the weight is on the LCA, and pry on the lower ball joints

With the car on the ground, and a friend to move the steering back, forth, LOOK for play in the tie rod ends, up/ down play in the idler arm, or any other play in any of the joints in the tie rod chain.

LCA bushings are difficult to REALLY check. If they are pretty bad, jacking up, releasing tension on the T bar adjustments (count the turns) and then prying on the LCA, but they have to be REALLY bad before this shows up.

Frankly, I'd just tear it apart and rebuild it.
 
It's hard really hard to say what it was like before. I only had the car with the slant 6 for about 6 months. It just feels like whenever I get into the freeway it wants to keep going in that direction off the road. Then I have to be careful because when try to straighten it to get back into the lane it will just want to keep going in that direction. Its crazy.

So, yea... I avoid the freeway. Around town its ok though.
 
sounds like caster angle or sloppy steering box, if the linkage ain't shot. That offset bushing kit will help solve some of that, the rest of the rebuild should tighten you right up. Dont over look your column coupler and gearbox. Lastly verify all your rear suspension is tight.
 
myasylum said:
Thanks dude!

Excellent post!

I think the control arm bushings come with the kit?!

I did hear the front sway bar (If I chose to go that route? ) are different depending on the K Frame. Is that part true?

Thanks!

Oh, I never changed the bars. Its been like this for 3 years. Maybe that's the whole problem?:banghead:
Click to expand...

The upper control arm bushings DO come with the kit, but not the offset kind that you can use to improve your alignment. You'll just get standard UCA bushings with the kit.

The sway bars are different depending on the year of the K frame, but not on whether its a /6 or V8. 67-72 get one kind, 73-76 get a different one.

Sounds like you need to get into the entire front end. Replace all the bushings, which will require disassembling the entire thing. While its apart, look for cracks, broken parts etc. Make sure you take a look at the frame too, both the upper and lower control arm mounts are prone to cracks. Then reassemble with new bushings, ball joints, tie rod ends etc. And since the torsion bars will have to come out to do all that, put in a new set when you reassemble.

The torsion bars are not causing the problem your describe, and I didn't intend anyone to think that they are. But they aren't helping, and since you already have to do all the work to remove them, there's no sense in putting old worn out /6 bars back in the car. Even if you hadn't upgraded to a V8!
 
That sounds hard :/

I will do that though! Thats about $650.00 in parts.

The Question remains as far as the front end kit...

Just Suspention,

Or

PST?

It seems l might as well stick with the Polygraphite High Proformace kit huh?

Just Suspnetion seems to have the best deal on the 1" torsion bars.

Thanks!
 
some guys complain about the poly, others swear by it. You might wanna do a search on those parts . I didn't catch if you got front disc or drum . BTW going from /6 bars to 1 inchers, holy cow , that's gonna be a stiff ride if you aren't ready. Was it factory sway or would you be adding that in?
 
I have front disc. Its a 73.
I would be adding a sway bar. It didn't come with one.
I wouldn't get that for awhile anyway. I just want to get this car road worthy first.

What size bars should I be looking for?

I know quite a few guys on this forum bought the 1" because of the price @ $199.00.
 
funwithfuel said:
some guys complain about the poly, others swear by it. You might wanna do a search on those parts . I didn't catch if you got front disc or drum . BTW going from /6 bars to 1 inchers, holy cow , that's gonna be a stiff ride if you aren't ready. Was it factory sway or would you be adding that in?
Click to expand...

The Just Suspension 1" bars aren't that stiff. I did that exact swap, /6 to 1" JS bars with my Duster when I dropped in the 318. Ride was pretty nice, even with the plain old Monroe's it had on it. Too nice in fact, I bought a set of 1.12" bars from Firm Feel to upgrade it again, they'll go in with a set of Bilsteins when I drop the 340 in it.

With 1" bars you'll find the ride is closer to that of most new cars. Still probably softer than most. These cars were ridiculously undersprung from the factory.

myasylum said:
I have front disc. Its a 73.
I would be adding a sway bar. It didn't come with one.
I wouldn't get that for awhile anyway. I just want to get this car road worthy first.

What size bars should I be looking for?

I know quite a few guys on this forum bought the 1" because of the price @ $199.00.
Click to expand...

Just get the 1" bars. The ride is still softer than most new cars, and your handling will be improved by light years.

As far as the kit, if you're going to get the Just Suspension bars I'd just buy their kit, you might even be able to swing a discount. The poly bushings are nice, but if you're not going to get new LCA pins I'd stick with rubber bushings. The poly bushings tend to squeak if they aren't lubed on occasion, and that would require greaseable LCA pins. Plus, the poly bushings are a little different than stock, so the shoulder on the new greaseable pins (from Firm Feel, Hotchkis, etc) is also a little different to match the poly bushings better. I run the poly bushings in my cars, but I also bought new greaseable LCA pins to go with them. And realistically, for a driver, cruiser, show car etc, the rubber bushings are just fine. I probably can't even tell the difference in handling between a new set of poly's vs a new set of rubber bushings.

If you call them up, see if you can get them to substitute Moog 7103 offset UCA bushings in for the plain ones. You'll want those either way to put a real alignment on the car when you're done.
 
If you just want to do it in more manageable pieces, then first go over everything as suggested above and see where the 'scary' problem is coming from.

I did the kit approach when I first got into this and am hesitant to push anyone that way. The stiffer (poly) bushings are best for those really into sporty handling. Otherwise, my suggestion is buy good quality replacement parts from the parts store. Moog and a couple of others I'm blanking on are generally still decent quality and good fit. The Moog 'problem solvers' are useful if you can't get enough caster.

Wandering and following the road are often due to loose wheelbearings, tie rod ends and toe out.

I'm too am not a fan of staying with the /6 t-bars Unless you will be drag racing. If/when you go to buy your new t-bars, make sure they are clocked. They will be a right bar and a left bar. Firm Feel's and Chrysler bars are clocked, and maybe some of Just Suspensions. While I agree that anything up to 1.04" will be OK, unless your really looking for sporty handling, anything down to .93 will be good.

More important for a reducing roll and overall response to steering input is a front sway bar. Firm feel has come up with a decent solution for cars without swaybar tabs, and you can see what Hotchkis, Helwig or Just Suspension may have. Skip the addco IMO. Some of what you are paying for is the thought and planning that went into making a bolt up solution that is not mickey mouse. Sway bar bushings are a good place to use polyurethane. Only reason not do the front sway bar would be serious drag racing. (again all IMHO).

All of this assumes the tires are in decent shape. Include them in your check up.
 
Mattax said:
If/when you go to buy your new t-bars, make sure they are clocked. They will be a right bar and a left bar.
Click to expand...

This isn't necessary depending on the bar. The clocking is just to set the ride height, and stiffer bars need less clocking for the same height.

The Just Suspension 1" bars are not clocked, they're the same left to right (until you install them, once installed they should stay on that side).

There can be ride height issues depending on how the bars are clocked, I've heard complaints about Hotchkis' A body torsion bars and even PST's 1.03" bars not having enough adjustment to get the car back to stock ride height. With the JS 1" bars I was able to put the car pretty much at stock ride height. Granted, the adjusters were almost all the way in at that point. But since I run the car lowered a bit there was more than enough adjustment, I backed off the adjusters a little to put it where I wanted it.

This is a shot of my Duster with the 1" JS bars installed, and the ride height I had it set up at with some adjustment still available to raise the car. For reference, those are 225/60/15's.

IMG_3619.jpg
 
Agreed it is not always neccessary. For example, I used 30 degree equally clocked bars from 1989-2003 on my '67 Barracuda. But for the OP, I recommend using clocked bars. Even some people who are really into doing suspension mods are not always happy to deal with non-clocked bars (as we have all recently been made aware).
 
Good reading guys!

I called a shop for pricing. They quoted me $900.00.
That's $1600.00 for parts and labor.

I just may attempt this myself.

Any advice?

It seems PST has 10% off for forum members. Maybe I will go that route after all?
They have the 1.03 torsion bar you were warning me about though. Maybe I should call them first and address those concerns.
 
That PST kit is pricey. You can probably do much better by shopping around on ebay and rockauto and piecing together a kit. I did. I re-used parts that were tight, like the upper ball joints and tie rod ends. The biggest slop is usually from the rubber bushings, lower ball joints, and idler arm. But those usually cause just rattles when going over bumps, not what you describe.

It sounds like your car wants to wander. That is usually from a bad toe-in setting, i.e. "toe out". That can result from the front end sagging. Did you set the ride height (per manual) after putting in the heavier V-8? If not, do so first. You can check toe-in with a ruler, front to back across the front tires (see youtube). Before that, just hold a 4 ft level or 2x4 along each front tire and sight at the rear tires. The fronts should be ever so slightly toed in. The idea is that when driving, they are pushed back from play in the steering and become close to perfectly straight, but never toe out (bad).
 
A genuine Chrysler-Plym or Dodge shop manual is very helpful, experienced or new to the game. Also very helpful are the old Master Tech service pamphlets archived at Imperial Club dot org.

Use suggestions in post #5 to track down the problem if it is looseness in some joint. Start with the steering. Jack only one wheel up and move it in and out at top and bottom (wheel bearings) and then left and right. You may need a helper so you can see where the slop is if any underneath (tie rod ends, steering arm or box, idler). Then go check the suspension joints. Use wheel chocks and jackstands if you go underneath the car.

Morris Quay is one of the other mfcs that used to be considered quality. Search around and see if it seems to be true still.
Lemme say I bought my first kit from a Kanter spinoff and it came with low quality tire rod ends that were grease came out all around the crimp. Needless to say I went to the local parts store and bought some good name brand ones before even using the kit ones. If you buy a kit, it might be worth asking for this sort of info.
 
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