Suspension advice

[dustoff440]

I have a 70 dart /6 with a factory front sway bar and disc brakes. I would like to increase the handling of the car and need some advice on front and rear shocks and the addition or change of items to increase handling characteristics. I should mention that I am on a budget.

 

[1968FormulaS340]

If you are on a budget just do a good stock rebuild with some KYB shocks and a good performance tire. Follow that up with a good alignment.

If money allows replace the /6 torsion bars with something larger and go with one of the XHD rear springs.

 

[idrift]

I have my 340 torsion bars out at the moment and am considering going to
1" bars. The 340's are .870 which is a big step up from you /6ers. I would
let them go pretty cheap if you are interested.

 

[dustoff440]

I would consider the bars, did you have a price in mind? Thanks, Brooks

 

[yellowdartdave]

Bigger front sway bar AND an aftermarket rear sway bar will make a huge improvement.

 

[rumblefish360]

Bigger front sway bar AND an aftermarket rear sway bar will make a huge improvement.

Ditto! ADDCO makes sway bars for the MOpars and was in the MP boks for years.

The T-bars are for up and down movement mostly. And while a thicket T-bar is nice in this area, the ride may not be what your expecting.

The KYB shocks are stiffer than most other simple replacement shocks at a reasonable price. Serious shocks get expensive very quickly.

 

[wracks71]

i have the big sway bars from firm feel. after buying "another" brand,these are much nicer! 1 1/8 front,3/4 rear. if you can weld,weld in subframes make a HUGE difference.

 

[tom340]

Planning to upgrade front SB, install rear SB hopefully before summers is out. Also KYB's , shocks in the car now plain suck.
Anyone recommend PST polygraphite front end rebuild kit, or stay with the OEM rubber bushings?

 

[Vs29H1B]

Use poly graphite bushings in the front sway bar and links, use Moog bushings in the strut rods, and the control arms (upper and lower).

Use poly graphite bushings in the eyes of the rear leaf springs. You will notice a substantial improvement takign this route.

Use Spicer Pro line ball joints (instead of Moog) because the quality control is excellent. Most Moog ball joints are not as there were just a few years ago, due to the outsourcing problem (Moog builds their stuff off shore).

Use 340 torsion bars and eitehr the Edelbrock or QA1 shocks.

Call ESPO (Springs and Things) for all your suspension needs. Great service and prices.

 

[bjkadron]

First off in handling upgrades would be a good set of tires. As they are the only thing connecting your car to the road. After you have them you can concentrate on making them perform the best they can.
The other upgrades you will "feel" the most will be as follows and why.

Anti-roll (sway)bars- Because if it feels like your going to flip the car over your not going to want to drive it hard. Also it keeps the tire in contact with the road by controlling the roll so the tires don't get positive camber(tire tipping over) so the tire can stay as close to flat as possible therefore getting the largest contact patch available and maximizing available grip.

Bushings- Are what keep everything in alignment. Small changes in alignment are VERY noticeable while driving and can make your car feel like its alive! And not in a good way. A good set of poly bushings will keep all the suspension attachments where they should be. Stock rubber will deform under hard cornering.

Shocks- are what actually keep the tires in contact with the road when your going over bumps. they damp the up and down motions so the tire doesn't bounce up and down like a lowrider with a set of hydraulics. The compression/rebound settings of the shocks will affect the fore/aft weight transfer (drag shocks maximize transfer road-race type minimize).

Springs (and torsion bars)- Will help more for the fore/aft movements like accel./braking forces. however A-bodies have a large amount of anti-dive built into their front suspension so braking forces will not affect it as much. Rear leaves should have some amount of anti-squat built in so it will keep the weight from transferring towards the rear too much. Also the compression/rebound damping on the shocks will affect this(see above). Spring rates do affect roll stiffness but they also affect vertical(bump) stiffness. so they will penalize ride quality and suspension travel. Most experts recommend Soft springs & stiff anti-roll bars for street driven cars. although stock mopar spring rates are Really soft.

Hope this helps!

Benjamin
(Bjkadron)

 

[Thropar]

Use 340 torsion bars and eitehr the Edelbrock or QA1 shocks.

Summit's price just dropped $10 each on the Edelbrock IAS shocks. I'm going to try them out instead of the KYB's I used to run.

 

[2 Darts]

Make sure the stuff that's there works properly, first. Otherwise, you'll just be chasing problems around (if there are any). I agree that replacing worn front end bushings and a good set of shocks is a good start. Replacing the bushings with polygraphite will make things a bit more precise, but they are prone to squeak. (I have not had the problem personally, but others on the board have.) Recommend a gas charged shock absorber.

I like adding a rear bar. Most aftermarket bars mount on the rear axle which adds to unsprung weight making the car ride a little rougher. They work fine nonetheless. For the Demon, I fabricated mounts to put the bar on the body, which makes the weight of the bar part of the sprung weight of the car.

Nothing will transform a car's handling more than a good set of tires. Here's where things get problematic (also, expensive) for A-bodies. A good performance tire likes a lot of rim width. Only disk brake cars made after 1972 escape the curse of the small bolt pattern (SBP) wheel. These two things work against each other. Mopar's 14 inch wheels for the A-body were either 4½ or 5½ wide. (The wheel centers were also notoriously flexible.) This is not conducive to high performance from the tires. The good news is that the wheel wells will take a 7" wide rim with 4¼ or 4½ inches of back space without problems.

As far as tire sizing is concerned, getting things to work up front without interference is the issue. I've got 235/60-15s on the front of 72 Demon using Mopar cop car wheels that are 7" wide with 4½ of back spacing. Ride height is set to the minimum within the recommended range. I can drive aggressively on smooth roads without any rubbing. This is the maximum front tire size I'd recommend.

In the current situation, you're limited in choice of aftermarket wheels to Cragar s/s or Wheel Vintiques SBP Rallye wheel reproductions. Not sure about the Cragars, but the WVs can be had in 14 and 15 inch diameters for the SBP Mopar. Back in the day, I think, Ansen Sprints were made in wide widths with SBP.

Nice looking Dart in your avatar. Good luck.

 

[limelite70]

If Your On A Budget,
Try Some Good Shocks Like 68 Formula Said,
And Go From There.

 

[PST]

Planning to upgrade front SB, install rear SB hopefully before summers is out. Also KYB's , shocks in the car now plain suck.
Anyone recommend PST polygraphite front end rebuild kit, or stay with the OEM rubber bushings?

KYBs are a great shock! We offer both Polygraphite and OEM-type rubber bushings. Rubber replacement bushings will just bring your car back to factory handling levels. Polygraphite bushings are near-zero deflection and are a great upgrade from rubber - plus, they will never dry rot so they will last practically forever.

If you grease Polygraphite liberally before installation, it shouldn't squeak. That being said, from time to time (quite rare) we do hear about people who install their bushings properly but still hear some squeaks.

Hope this helps!

 

[dustoff440]

Thanks for all the great advice guys!! I haven't had the car all that long and I had it up on a lift a few days ago and I was surprised to discover that the ENTIRE front end including the sway bar bushings has been fairly recently rebuilt. I have almost enough money to go with a good set of tires and good shocks. I found a set of used .870 bars as well. Everything else will have to wait.

 

[dartley]

Thanks for all the great advice guys!! I haven't had the car all that long and I had it up on a lift a few days ago and I was surprised to discover that the ENTIRE front end including the sway bar bushings has been fairly recently rebuilt. I have almost enough money to go with a good set of tires and good shocks. I found a set of used .870 bars as well. Everything else will have to wait.

Well you've certainly gotten much advice. But one thing you really should have said to begin with was your intentions and expectations.

It sounds like you just want moderate improvements and that you are not planing on going rally racing or anything like that.

If this is the case, then I think you are on the right track concerning tires, 340 Tbars and shocks. But one caveat ... don't just put on the heavier Tbars if the rear is still on mushy leafs - you'll end up with understeering, because the rear will transfer the "twist" back to the front of the car, which will then want to wash out - same as just adding a rear ARbar without replacing the front ARbar with a stiffer one - these need to work in pairs. Front and rear springs should always be in matched sets.

Also bear in mind that the stickier the tire the more roll you'll get with your existing suspension.