I'm working to improve my rear suspension even more. I have a 68-70 B body rear with a 1/2 inch spring relocation under my 70 Duster. I have the front suspension pretty much dialed in with the exception of shocks, this goes for the rear as well. I think I've settled on the Hotchkis/Fox shocks. I'm looking at doing some autocross and am wondering if I need a rear swaybar and if so, which one. I have stock leaf springs which seem to be OK, but maybe there isroom for improvement there. I've been seeing posts about Hotchkis leaf springs and thinking maybe with them and the shocks, a sway bar may not be necessary.
A body with B body rear...Sway bar?
- Thread starter Mojoe9955
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The best your stock leaf springs could be is 110 lb/in, those were the XHD's. But more than likely they're either 90 lb/in or 100 lb/in. In either case that's going to be a bit on the soft side, most of the autoX guys are running ~130 lb/in springs (Eaton from Bergman, Hotchkis, etc). I have a set of AFCO's that are 120 lb/in, which I run with a 7/8" E-body Hellwig sway bar and hotchkis shocks. Pretty much everyone doing autoX on a regular basis runs a rear sway bar with those springs (as well as a front bar).
As for which sway bar, the Hellwig and Hotchkis A-body rear bars are both good options, although it doesn't look like the Hotchkis rear bar is currently available. The Hellwig is a little easier to install, you can do it without welding anything where the Hotchkis bar has hangers that weld onto the frame rails.
The A-body Hellwig bar is 3/4" and should be just fine. I went with the E-body bar because of the 1/2 offset I also have on my 68-70 B body rear, but the way it mounts it still puts the end links at a bit of an angle. I have a set of heim jointed end links to solve this issue, but really just staying with the A-body bar is probably a better bet for most folks.
The other thing is that you do want to keep the car balanced, so, you will want a front sway bar if you don't already have one, and your front torsion bar diameter is also an important consideration. As well as your tires. If you're running the usual all season radials and stock-ish sized torsion bars up front, you won't want to go crazy with the rear leaf spring rate either. If you're running wide tires with a sticky compound and large diameter front bars, you'll need the higher rear spring rate too.
I have front and rear sway bars on my 67 fastback, and while it corners extremely flat, it tends strongly toward understeer. For autocross I would think you would want to be able to rotate with power; i.e. oversteer. I would try it w/o the bar to start.
On the other hand my car is very stable at high speeds, but that isn't an issue with autocross.
On the other hand my car is very stable at high speeds, but that isn't an issue with autocross.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I don't do autocross. The only track we have is Not dedicated and is over an hour away.
My car has ONLY a front sway rear bar, 1.03 bars and plain old 3-way adjustable shocks. I have had 245s on the front and still do run 295s on the rear. Rear springs are Stock FormulaS with a full main-leaf added. The car is lowered to about 5.75 under the lowest part of the K, and the sills are very nearly level.
But, my car, on the street, turns in nearly neutral, and exits with oversteer, adjustable with the throttle. If she gets too far off line, I just put a lil toe on the clutch, and she snaps back to line, as the rear tires regain grip. But mostly, the tires are screaming in second gear, with the fronts at near full-lock, lol, cuz that's what I like, lol.
IDK, she's the best handling street-machine I've ever had. But, she's got over 135,000 miles on the chassis now, so, I tend not to push too hard any more. Plus, I'm over 20 years older now as well.
At one time, like two decades ago, I had thought to put a rear bar on, but my Shocks, and near-flat over-load springs, are doing a pretty good job back there. Actually, a Great job, on the streets and parking lots..
My car has ONLY a front sway rear bar, 1.03 bars and plain old 3-way adjustable shocks. I have had 245s on the front and still do run 295s on the rear. Rear springs are Stock FormulaS with a full main-leaf added. The car is lowered to about 5.75 under the lowest part of the K, and the sills are very nearly level.
But, my car, on the street, turns in nearly neutral, and exits with oversteer, adjustable with the throttle. If she gets too far off line, I just put a lil toe on the clutch, and she snaps back to line, as the rear tires regain grip. But mostly, the tires are screaming in second gear, with the fronts at near full-lock, lol, cuz that's what I like, lol.
IDK, she's the best handling street-machine I've ever had. But, she's got over 135,000 miles on the chassis now, so, I tend not to push too hard any more. Plus, I'm over 20 years older now as well.
At one time, like two decades ago, I had thought to put a rear bar on, but my Shocks, and near-flat over-load springs, are doing a pretty good job back there. Actually, a Great job, on the streets and parking lots..
I have 1.03 t-bars, QA1 adjustable strut rods, lower control arm stiffing plates and delrin bushings from BAC, a 11/8" Hellwig sway bar, stock upper control arms with Moog offset bushings. I'm running 255/40/18 tires. Outback I moved my leafs 1/2" inboard with sliders like yours and modified the stock front hangers to accomplish that. I have 275/40/18 tires and have plenty of room to go bigger. The shocks I am currently running are KYB, altogether though it really handles pretty nice. I'm trying to post some pictures but, while I was able to in previous posts for some reason I'm unable to now 
While it depends on what torsion bar and leaf spring rates you have, typically adding a rear sway bar tends to reduce understeer.
I have 1.03 t-bars, QA1 adjustable strut rods, lower control arm stiffing plates and delrin bushings from BAC, a 11/8" Hellwig sway bar, stock upper control arms with Moog offset bushings. I'm running 255/40/18 tires. Outback I moved my leafs 1/2" inboard with sliders like yours and modified the stock front hangers to accomplish that. I have 275/40/18 tires and have plenty of room to go bigger. The shocks I am currently running are KYB, altogether though it really handles pretty nice. I'm trying to post some pictures but, while I was able to in previous posts for some reason I'm unable to now
With that combination of things up front you will want the rear sway bar, especially with the factory leaf springs.
Yep, it'll work fine. The Hellwig is a rear axle hung bar, the end links mount to the frame rails, so the wider rear axle doesn't matter. You can download the installation instructions at Summit for the Hellwig 6907, it has pictures of all the mounting points.
I used the E-body bar because it's larger in diameter, but the widths of the rear bars are within an inch of each other. But like I said, the supplied end links end up at a bit of an angle with the E-body bar. It works better with a full 3 relocation and mounted to the relocation spring box.
Thanks, I'm going with the Hellwig bar, but am have a hard time finding the right Hotchkis shock. Anyone have part numbers or source? Are QA1 shocks an option? I see they have a sway bar, but it seems like it's more a part of a "system"
dano
Evil Handy Man
The housing length really doesn't have anything to do with how the rear bar will fit unless its narrowed down to look like it has a pair of pavement rollers under it. As stated by 72bluNblue, look to Hotchkis, Hellwig and Firm Feel for bars, down load their directions to see how they install and it will become clearer. Of the 3 the Firm Feel bar installs like the stock rear vars did on later cars. I have Addco bars front and rear, bought them long before there were any other options. The bars are good but the install hardware sucks, I've replaced a lot of it but look at their directions from 1982 and you'll get the idea.
The part numbers are listed at Summit, but they don't have anything available for Hotchkis shocks. Hotchkis has been thoroughly screwed up since they moved their shop, with lots of their parts going MIA. On the Hotchkis website it says to call them for pricing on the shocks, but that probably means check availability more than anything else.
RideTech has some good shocks as well, I know @BergmanAutoCraft carries those although it looks like the "suspension" section of his website is being funky.
I've been trying BAC and have had no luck either.
Try sending him a message here, ive had contact with him in the last few days. Could be his shopfront is closed for the holidays?
Looking at it from a price point, I went with a 7/8 G-Max rear sway bar and Bilstein shocks front and back from PST.
With free shipping and the 10% FABO discount, I couldn't resist. Another factor was if they work as they should and I see no reason why they won't, I'll leave them on. If they don't, and I feel the need to improve my suspension further, I can put them on my 74 Duster project which definitely has room for improvement in the suspension department. In the meantime, using car guy math, the money I saved, about $600, will be going towards getting the transmission sorted on the 74. The KYB shocks from the 70 can go into my 72 Demon which is another story, but l'll save that for later. All in all a decent compromise and a pretty good start to 2025. Thanks for the input guys. HAPPY NEW YEAR
With free shipping and the 10% FABO discount, I couldn't resist. Another factor was if they work as they should and I see no reason why they won't, I'll leave them on. If they don't, and I feel the need to improve my suspension further, I can put them on my 74 Duster project which definitely has room for improvement in the suspension department. In the meantime, using car guy math, the money I saved, about $600, will be going towards getting the transmission sorted on the 74. The KYB shocks from the 70 can go into my 72 Demon which is another story, but l'll save that for later. All in all a decent compromise and a pretty good start to 2025. Thanks for the input guys. HAPPY NEW YEAR
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Best way to reach me is 516.384.6438 or [email protected]. I’m not on the board a lot due to the shop workload.
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