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5 leaf or 6 leaf springs?
https://slantsix.org/forum/viewtopic.php?t=55315		 Page 1 of 1
Author:  '67 Dart 270 [ Fri May 09, 2014 7:07 pm ]
Post subject:  5 leaf or 6 leaf springs?
Should I use 5 leaf or 6 leaf springs on my 67 dart?

I want it to handle well, not too stiff in the rear. My current springs are 5 leaf, very mushy, but I'm told they can be recurved.

Regardless, there was an earlier discussion on the boards that ESPO makes a nice 6 leaf spring that works well. http://www.springsnthings.com/ And, I was pretty set on those. I want stock height, not too stiff, but certainly what I have now is way too soft.

My brother, an apparent expert, told me that under no circumstances should I get 6 leaf springs, they'll be way to stiff for my application.

Further thoughts? I actually ordered the 6 leafs today, but since they're way back ordered, I figure I can change that in plenty of time.

brian
Author:  wjajr [ Sat May 10, 2014 6:04 am ]
Post subject: 
Quote:
I want stock height, not too stiff, but certainly what I have now is way too soft.


Old de-arched springs will feel soft, they are fatigued, worn out, getting close to their cycles to failure point, also these old cars feel and are sprung much softer than today’s cars, so I’m not surprised the seat of your pants are feeling mush (no pun intended regarding muddy rudders here, nothing to see, please keep reading on). {;-I} wink-wink


I hope you are planning on increasing the front spring rate by installing larger torsion bars to balance out suspension dynamics and respective bushings; in other words having front and rear axle reacting in like, or the car will feel like two different vehicles attached by a hinge behind the front seats. In other words the mush will migrate to the front axle.



FYI: I installed six leaf ESPO springs on my ragtop five years ago along with 0.940" Firm Feel T bars, sub frame connectors, new bushings, front anti sway bar, and rebuilt firm feel level 2 PS gear. She now handles like a modern car, and ride is plesent.
Author:  '67 Dart 270 [ Sat May 10, 2014 9:07 am ]
Post subject:  Thanks so much,
Yes, I plan to balance it out with better T-bars in the front (I have .890/.891 set), and I have a 73-76 k frame, sway bar, upper and lower control arms, etc for eventual upgrades in the front (going to disk brakes when I swap out the front suspension). My 7.25 rearend is close to meeting its end, and I have a newly rebuilt 8.75 to drop in, but I'm having to decide on leaf spring choice.

Is it true that you don't need a year sway bar with the 6 leaf springs, is that overkill? Perhaps a "light" one?

thanks again,

Brian
Author:  '67 Dart 270 [ Sat May 10, 2014 9:09 am ]
Post subject:  also....
Did you have to "break in" your six leafers by putting weight in the trunk, or was the ride OK from the start?
Author:  wjajr [ Sat May 10, 2014 3:39 pm ]
Post subject: 
[quote]Is it true that you don't need a year sway bar with the 6 leaf springs, is that overkill? Perhaps a "light" one?[/quote]

I do not have a rear anti sway bar on the Dart. One has to be careful when installing a rear anti sway bar on an A body, they can become tail happy (excessive over steer). So far my car has been stable in corners, but will come around real fast on wet roads when both tires are spinning from too much throttle with a little steering died in. Josh can school you in rear sway bars.


[quote]Did you have to "break in" your six leafers by putting weight in the trunk, or was the ride OK from the start?[/quote]

No break in… Your old springs are broken in; fatigued, not something one wants with new springs. Install them, and go for a ride. Like I said above you really should upgrade the front end at the same time for best results. I just love driving my Dart, it corners flat, no nose dive under hard braking, no keeling over during excessive steering input and no bottoming out on bump stops; goes where I point it with no fussing.

If you talk with ESPO they will tell you that the six leaf pack has about the same spring rate as the five leaf pack. What is different is the flex pattern between axel and front hanger which prevents some of the spring osculation under hard acceleration. I have an 8 ¾â€￾ 489 Suregrip with 10â€￾ drums, and that is a lot of metal under there the springs have to control. Except for the missing big block I have cloned a Cuda S package.
Author:  '67 Dart 270 [ Sat May 10, 2014 6:40 pm ]
Post subject:  thanks again...
That's very helpful information. I'm pretty comfortable with the 6 leaf decision, and you've only reinforced that.

Yes, I heard the same thing about rear sway bars on the A-body.

I was collecting suspension parts for the front and rear. As fate would have it, my 7.25 is dying before I was ready to do the whole job. So, I'll do the rear first, but I won't wait too long after to do the front. I have almost all the parts for the front, just need a few tidbits from firmfeel and the disk setup. The front will be a bigger job, as I'm swapping out K frame, etc.; but I'd imagine once that rear upgrade happens, it'll be more crucial to do the front... I have a lot of body roll now, once the back is upgraded the front is going to feel really freaky until it gets its upgrade.

b
Author:  wjajr [ Sun May 11, 2014 4:41 am ]
Post subject: 
Yup front connected to rear via bungee cord tight. LOL
Author:  WagonsRcool [ Sun May 11, 2014 8:29 am ]
Post subject: 
Quote:
So, I'll do the rear first, but I won't wait too long after to do the front.
Don't wait very long- oversteer on A-body ain't no fun (I once broke a front sway bar link just before going into some "fun" twisty curves :shock: ) You can mitigate this a little by raising front tire pressure to max sidewall rating & run rears at 5-7 psi less.

I'd finish all the front suspension work & try it out before thinking about a rear sway bar. Again, you don't want the rear to have too much roll resistance compared to the front. It will reduce lean but you'll have to tweak tire pressures, front & rear bushing/link materials, f & r spring rates, etc in order to get everything balanced.
Author:  '67 Dart 270 [ Sun May 11, 2014 7:21 pm ]
Post subject:  rear end
Yes, I'm told that Chrysler, for the day, was very far advanced and that their rear leaf spring suspension was ahead of its time, engineered to control body roll, etc.

b
Author:  2 Darts [ Sat May 24, 2014 2:27 pm ]
Post subject: 
I installed 6-leaf rear springs on a 73 Dart Custom. It took about a month for them to settle down to slightly higher than stock. At the same time, I replaced a lot of the other suspension components and radically changed the front suspension settings. As a result, I'm unable to tell what is attributable to simply the rear spring change.

RE: Rear anti-roll bar. Wagons and convertibles are less nose heavy than the sedans and hardtops. This means that they are more likely to display oversteer if a rear bar is installed.
There are two mounting techniques for a rear bar, bolted to the axle or bolted to the body. The 76 A38 A-body police package used the latter method. Virtually all aftermarket bars use the former. My personal preference is for the body mount, which I have on my Demon. I have to go crazy with the go pedal to get the rear to kick out.
Author:  Sam Powell [ Mon May 26, 2014 5:20 am ]
Post subject: 
Quote:
I installed 6-leaf rear springs on a 73 Dart Custom. It took about a month for them to settle down to slightly higher than stock. At the same time, I replaced a lot of the other suspension components and radically changed the front suspension settings. As a result, I'm unable to tell what is attributable to simply the rear spring change.

RE: Rear anti-roll bar. Wagons and convertibles are less nose heavy than the sedans and hardtops. This means that they are more likely to display oversteer if a rear bar is installed.
There are two mounting techniques for a rear bar, bolted to the axle or bolted to the body. The 76 A38 A-body police package used the latter method. Virtually all aftermarket bars use the former. My personal preference is for the body mount, which I have on my Demon. I have to go crazy with the go pedal to get the rear to kick out.
Explain further please. What is the layout for body mount? Rear of front? It seems the mufflers will be in the way. Can you supply a photo?

Sam
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