Handling 74 Duster

I’ve got a 74 Duster 360. And a 70 340 Dart. They both drive well but what else have you guys done to make your cars handle better?

Subframe connectors, 1.03" or larger torsion bars, sway bars and good shocks go a long way to making these cars handle very well. I also put tubular upper control arms and stiffener plates on my lower control arms.

Cley

89on35s said:

Subframe connectors, 1.03" or larger torsion bars, sway bars and good shocks go a long way to making these cars handle very well. I also put tubular upper control arms and stiffener plates on my lower control arms.

Cley

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What’s your caster set at

Get the right alignment specs into it and a good set of wheels and tires.

Parts come next.

-1* camber, 2* caster and 1/8" toe in I think.

Cley

hopefully that is negative camber

Suspension work:
1.03" (or bigger) torsion bars ------------------------$250-$355
Tubular UCA’s (PST, FFI, etc)------------------------$350
Adjustable strut rods (PST SR 14385)---------------$279
Solid tie rod sleeves (PST SAS 440S)----------------$49
LCA boxing plate (PST LCAPLTMOP621)-------------$14.50
Greasable LCA pins (FFI w bushings)----------------$135

Helwig tubular front sway bar 1 1/8” #55905 (73+ K)--$175
Solid rear 3/4” #6907--------------------------------$237

Rear Springs: 0 arch, something in the 120 lb/in to 130 lb/in rate

Energy suspension 1" shackle bushings 2-2117G----$9

Bilstein RCD shocks(RCD-70-56663)------------------$410

Grand total on that is about $2,300, that's got a little extra built in depending on where you shop and what you buy. These prices are a little old at this point, you may find they're a little higher now.

Chassis work:
Subframe connectors (1.5" x 3", .083" to 1/8" wall)
Torque boxes (US Cartool)
Shock tower to firewall reinforcement (US cartool or tubular "J" bar)
Lower radiator support reinforcement (US Cartool)

Tires:
If you really want to handle, you need to go 17" or 18" rims. BFG T/A's and Cooper Cobra's aren't good handling tires, they're all season hockey pucks with outdated designs and compounds. You can get your car to handle decently for an old muscle car with them, but they will be your limiting factor as soon as you start upgrading your suspension. If you goal is just to handle better, they're ok. If your goal is to truly handle well, they have to go.

Alignment:
-.5° to -1° camber, +3° (minimum) or more caster, 1/16" to 1/8" toe in

For the explanation- I recommend tubular UCA's because you can't really get more than +3° of caster with the stock UCA's and offset bushings. If you keep the BFG T/A's then the stock uca's and the Moog K7103 bushings will be ok, but really you want more caster than they'll give you. +5° is awesome, I run +6.5° but my set up is more extreme with tires and torsion bars. I recommend adjustable strut rods to eliminate binding on the LCA travel. The stock set up is "one size fits most" that doesn't usually fit any particular car all that well, and if you upgrade the LCA bushings you need to tune the strut rod length. I used to recommend the Mopar Oval Track rear springs, but their quality has been terrible lately and I won't recommend them until they improve that. It's a shame because they used to be a good, low cost option for an improved rear spring, the other options like Peter Bergman's Eaton springs or the Hotchkis springs are much more expensive.

US Cartool makes great chassis stiffening parts. The only thing I'd skip is their subframe connectors, because really you need to fully strip the car to install those right. And even then you really need a lift or a rotisserie. Without those, just make your own out of rectangular tube. It'll work just as well, and it will be LOTS easier to install. I've done both, and I wouldn't do the US Cartool ones again.

I have more details on the specific stuff I've done to my car in my build thread, which is linked at the bottom of my signature

1969cuda340 said:

what else have you guys done to make your cars handle better?

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Much of what I've done is here, although not exactly up to date.: 67 Barracuda for Handling and the Road
Always refining, especially when new tires go on..

Now what should you do? that's a different question.
Front sway bar is the first place I always suggest to increase front roll resistance and remove compliance.
Details depend on what's on there now.

Mattax said:

Much of what I've done is here, although not exactly up to date.: 67 Barracuda for Handling and the Road
Always refining, especially when new tires go on..

Now what should you do? that's a different question.
Front sway bar is the first place I always suggest to increase front roll resistance and remove compliance.
Details depend on what's on there now.

Click to expand...

It has a front sway bar. I’ve rebuilt the ps box lowered the rear put as much caster as I can in it. I’ll probably ad a rear sway bar.

1969cuda340 said:

It has a front sway bar. I’ve rebuilt the ps box lowered the rear put as much caster as I can in it. I’ll probably ad a rear sway bar.

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Ok for street - maybe.
I'd put polyurethane in the sway bar links and bushings (with heavywall washer and tube on the links) first.
Then up the t-bar size - how much would depend on the tire stick, but .990 to 1.03" unless running high perfomance or (R-comp-autox or track) tires.
After that, decide from there what you feel it needs for where you feel its deficient, maybe shocks.
I'm always cautious with rear sway bars, especially on A-bodies. Too easy to end up in an oversteer situation at high speed or on a wet downhill curve.

Alignment followed by tires and shocks. You already have the factory handling package, which is very good by the standards of the time. That's basically what my son's Dart convertible has, except it is factory big block stuff that is also supporting a big block. Ride is very good and the handling is predictable. It can be improved, but at this time it is fine for a street car.

Jim Lusk said:

Alignment followed by tires and shocks. You already have the factory handling package, which is very good by the standards of the time. That's basically what my son's Dart convertible has, except it is factory big block stuff that is also supporting a big block. Ride is very good and the handling is predictable. It can be improved, but at this time it is fine for a street car.

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I think this is a valuable point. "Handling" means different things to different people. If you've never driven a Miata or a Lotus or some mid-engine sports car, your benchmark for a good handling car may be very different. 442s had a reputation for being good handling muscle cars back in the day...and they were! Today, the handling of a stock 442 would be considered "scary" and despite the still-respectable power:weight, it would get out-lapped handily on a road course by a Pacifica full of screaming toddlers.

Your suggestions are 100% valid, IMO. Performance tires, performance shocks and an alignment would make for a good handling car by the 1970s standards. It would be satisfying and fun to drive. Maybe that's what the OP had in mind?

IMO, if you want an objectively good handling car (that would hang with genuine sports cars), the stock components aren't going to get you there. It seems to me that @72bluNblu's formula is the prescribed path to making that happen...while still having something that resembles a Mopar. For example, as has been noted many times, the geometry of the stock UCAs just won't allow you to optimize caster and won't give you enough negative-camber to maintain an optimal contact patch under cornering conditions. Without bracing, the chassis isn't up to the chore of managing the huge grip potential of modern tires...and of course, chassis flex instantly spoils that carefully dialed-in alignment and adds all kinds of slop and unpleasant feedback. Eventually, you'll break windows, etc. There are lots of limitations to handling that simply weren't design priorities in the 60s when the platform came out.

Fortunately, these cars were masterfully designed. They're light weight, durable, simple, relatively well-balanced, etc. There's a reason why A-Bodies sold so well during their run...and they're objectively better than a lot of what came after them and there's huge potential to keep their performance relevant with upgraded components.