Rear sway bar advice

[SK8BALL]

74 charger 318
Has original front sway bar.
No rear sway bar.
Looking at adding a 3/4” rear bar.
Will that size bar play nicely with the factory front bar?

 

[Rusty knuckles]

I'm guessing you're going to want a bigger front bar or smaller rear bar. But I doubt you can get smaller than 3/4" rear. She might be a bit tail happy.

 

[topside]

Had a '70 Satellite wagon - basically ordered like a RR wagon - added a bigger (1 1/8" or 1 1/4") ft bar and a 3/4" rear bar.
Was a nice-handling car and could surprise people. It was pretty neutral.

 

[Runcharger]

I'm a big fan of rear bars, Add it for sure. It may be a bit tail happy but will be fun to drive that way and later you can up the front bar a bit if you think it needs it.

 

[Kern Dog]

It is curious that most people think that they are an "above average" driver....a statistical impossibility.
A tail happy car that oversteers is much harder to control than a stock car and it requires much more skill when driven hard. "drifting" may look like a silly sport for some die hard car guys but it really is a challenging thing to do. Immediate, evasive maneuvers with a car that oversteers often results in a spin. This gets far worse the faster you go.
The factory intentionally engineered these cars to understeer since this condition is the safest for the overwhelming majority of the drivers on the road. Cars that understeer almost always can be brought back into control simply by slowing down until the front end regains traction.
That said....I will state that for some, a car that handles in a neutral manner, one that corners with minimal body roll/lean is a much more fun car to drive. When a car is neutral but can be made to hang the rear end out with some application of throttle, it is even more fun but to get there requires some planning. Many muscle era Mopars had soft torsion bar rates coupled with stiff leaf spring rates. A small front sway bar added stiffness to the spring rate during turns and balanced the car out. Adding a rear sway bar to a car that has no front bar or a factory front bar is not a good idea if you encounter an emergency situation and have to react quickly. The parts have to match each other much like an engine build. You wouldn't use 12 to 1 pistons with a stock cam or put a huge carburetor on a slant six.
The best combinations are as follows:
Stock torsion bars & leaf springs with a factory front sway bar.
Stock torsion bars & leaf springs, larger front sway bar, small rear bar.
Larger torsion bars, stock leaf springs, stock front sway bar, small rear bar.
Larger torsion bars, stock leaf springs, large front sway bar, moderate rear bar.
Large torsion bars, stiffer leaf springs, large front sway bar, NO rear bar.

It is about "roll stiffness". The end of the car with the greatest roll stiffness will lose traction first. If the car has firm leaf springs and a rear sway bar, the car will oversteer.

 

[Runcharger]

Oh boy, I better leave this in the garage I guess. Not sure how I'm still alive.

 

[SK8BALL]

It has the original 48 year old leaf springs.
I’m sure they are a bit tired.
That will probably help a little with the oversteer.
Any suggestions on front bar size?
What size is the factory front bar on a 74?

 

[Runcharger]

Not sure on your car. On an E-body I believe the front bar was just under 1 inch and the rear 3/4. My 71 383 Challenger R/T with a rear bar was a bit tail happy. On my 70 Challenger 383 R/T the suspension was identical to the 71 except the factory did not add the rear bar and it pushed. Hence I don't think you're going to the hospital if you add the rear bar and there is a time lapse before tuning the rest of the suspension. Torsion bars and rear springs all add to the balance as well.
I added the rear bar to my 71 Road Runner and I loved it, it had the stock front sway bar, 098 torsion bars and XHD rear springs, but the weight bias was different having a Dana 60 in the rear and a 440 up front. Almost every car is different.

 

[Nacho-RT74]

As far I recall

Small block front sway bar, 7/8
Big block front sway bar, 15/16
Rear sway bar on both, 3/4

 

[chargervert]

Someone needs to reproduce the rear sway bar brackets in heavier guage metal than what the factory used. I have a couple of setups and they are all cracked.

 

[SK8BALL]

I am going to move forward with the
3/4” rear bar. Will upgrade the front
if needed.
Thanks everyone for your information
and suggestions.

 

[JR_Charger]

I'm shopping for a rear bar. I've currently got the QA1 bar in front, which is 1 1/8." I may change to Hotchkis's front bar in the future, does anyone know what size that one is? I'd like to get my "system" right. Firm Feel has a 7/8 rear bar, which may match their 1 1/4 front bar. PST has a 3/4" rear bar. No idea what size the Hotchkis bar is.

I'll be using the 50+ yr old stock springs until I can get the final weight of the car. If the car rides better with factory springs and a rear sway bar, I'd rather do that than stiff springs and no sway bar.

Someone needs to reproduce the rear sway bar brackets in heavier guage metal than what the factory used. I have a couple of setups and they are all cracked.

Firm Feel makes new ones, but I don't know if they are any stronger or not.

 

[Cranky]

I'm a proponent of big bars and a bit soft springs. The car will usually ride better on the straight line highways but will still corner well and not ride like a 3/4 ton truck when they have the heavy springs installed......

 

[Kern Dog]

I'm shopping for a rear bar. I've currently got the QA1 bar in front, which is 1 1/8." I may change to Hotchkis's front bar in the future, does anyone know what size that one is? I'd like to get my "system" right. Firm Feel has a 7/8 rear bar, which may match their 1 1/4 front bar. PST has a 3/4" rear bar. No idea what size the Hotchkis bar is.

I'll be using the 50+ yr old stock springs until I can get the final weight of the car. If the car rides better with factory springs and a rear sway bar, I'd rather do that than stiff springs and no sway bar.



Firm Feel makes new ones, but I don't know if they are any stronger or not.

Sorry, I don't recall which model of car that you have. It does matter since not all B body cars respond the same.
My red '70 Charger handles great. Very little body roll, great ride considering the spring rates, just a little brake dive and mostly neutral.
1.15" torsion bars.
1.25" hollow front sway bar. Moog ball joint style end links.
urethane strut rod bushings, rubber everywhere else.
Offset UCA bushings.
Borgeson steering box.
MP XHD 440-4 speed/Hemi leaf springs with 6 full leafs and a single half leaf on the forward side.
3/4" rear sway bar from a 1983 Imperial. Same unit was OEM on the M body police cars from 1980-89.
I have tried numerous combinations and this one feels the best. I have not reached the limits to determine if it ultimately understeers or oversteers since I switched from a solid 1 1/4" front bar to this hollow one. It used to have very slight understeer that could lead to oversteer with application of throttle. Theoretically, going to a Hollow front bar of equal diameter should result in an increase in oversteer but I've yet to push it hard enough to see any.

 

[JR_Charger]

Where'd you get the ball joint style end links? I've never heard of those.

I may go with PST's 3/4" rear bar, if their bushings for it are polygraphite. The less chance of squeek the more better.

 

[Kern Dog]

Where'd you get the ball joint style end links? I've never heard of those.

I read about them in Mopar Action magazine. I got mine through Rock Auto. I covered the modifications that I did to make them work in this thread:

Re-Rebuilding the 440-493 in a 1970 Charger

The sway bar end link portion begins at post # 226.

I had to shorten mine to allow for proper fitment. I cut, welded, sandblasted and then........

.....coated them with the RPM paste.

These links swivel on ball joints. No bushings to squeak or flex.

 

[JR_Charger]

Fascinating. May have to pick up a set one day, if I ever get a chance to pick up welding.

Does the RPM dry?

 

[Kern Dog]

The RPM is a semi dry paste. I heat up the part and brush the RPM onto it. The RPM can then be rubbed into the metal by hand or with a towel. It keeps the unpainted metal parts looking new.

 

[Dibbons]

The best combinations are as follows:
Stock torsion bars & leaf springs with a factory front sway bar.
Stock torsion bars & leaf springs, larger front sway bar, small rear bar.
Larger torsion bars, stock leaf springs, stock front sway bar, small rear bar.
Larger torsion bars, stock leaf springs, large front sway bar, moderate rear bar.
Large torsion bars, stiffer leaf springs, large front sway bar, NO rear bar.

It is about "roll stiffness". The end of the car with the greatest roll stiffness will lose traction first. If the car has firm leaf springs and a rear sway bar, the car will oversteer.

On my '72 Satellite Sebring Plus 318, I currently have no sway bars. I have purchased a factory rear bar and I have installed PST 1.03" torsion bars (listed on website as 41" and 210 lbs/inch). Looks like I better be careful after the rear bar is installed. But wait a minute, I don't even know if the factory rear sway bar will fit a vehicle with a 8 1/4" differential???


Is there a source anywhere to find out what all the different Mopar torsion bar spring rates are?

 

[Dibbons]

I found a chart, but looks like part numbers are not factory because they start with a "P".