bully62

1972 plymouth duster with 275-60-15 bfgoodrich radial t/a tires. I am looking to go to coil over suspension currently have air shocks. I need your opinion on lift and brand.

DDodger

Why?

That is a SERIOUS question

Why? Do you want to modify your car and for what purpose?

bully62

Better ride and air shocks leak

demetri

Original torsion bar suspension is very well engineered, and likely superior to the aftermarket junk that is out there. There may be some aftermarket sets that are well engineered to match your car (not very likely), but why spend money on something that already works well?

bully62

I'm just looking to replace rear air shocks got torsion front end. I also need some lift so tires don't rub

Rooty

You could do a rear lift right at the axle/spring with spacers of sorts. Problem then may be the lift affects the car's sway behavior so then you'd probably have to put a set of quality shocks like Bilstein's on. Any time you raise or lower a car's rear, it affects the shock travel either on extension or compression especially considering one end of the shocks connect to the perch plate and the uncommon tilt front to rear means a fresh alignment is in order as now you have changed the castor value for the front suspension. Some people have used longer shackles in the back but most cars end up wobbly on the back like the feeling you get with air lifts. Anyway you'll figure it out and who knows maybe the tire size and backspacing of the rims will end up being the true issue. Good luck whatever you do.

Archer

bully -

The right way to do it is with new or re-arched springs. If yours are original, you might be surprised how bad they are when you take them off. The bushings are probably toast as well.

The guys at Firmfeel can send you new heavy duty springs with the ride height you want, but they are pricy. Off the rack springs will work, but it's more of a crap shoot for ride height. I just did a full Firmfeel suspension upgrade (front and rear) and "night and day" barely describes it.

Yes, you can use shackles or a lift kit, but it's a band-aid fix.

BTW - for performance the Chrysler torsion bar system are horrendous, but a proper coil-over up-grade, including rack and pinion steering can set you back $10K, and it just doesn't "look" right on a Mopar, IMHO anyway.

Archer

DDodger

Neither of the reasons you stated is a reason to throw away the original TYPE suspension. The front height is easily adjustable within limits. People like Hotchkiss (and others) have performance bushings and T bars if you want stiffer or not

Rear leafs can easily be replaced, re-arched, re-built and so on.

"This idea" that people get that converting to "some other" suspension IS NOT the "always answer." Many times, "alternative" front suspension is done for weight in drag racing. That is not a reason for a street car.

Drag Pak

Yeah , they really suck!

DDodger

Complete nonsense. There's quite a few guys into vintage road racing and Auto X who are using stock geometry, with great success

The main reasons for going to coil over (which requires a LOT of changes)

is lighter weight for drag racing, and for increased engine clearance for BB and hemi swaps. Bear in mind 426s were put in these cars a long time ago......with stock suspension.

bully62

What can I do to get rid of the air shock ride but still have enough lift to keep from rubbing tires on fender well lip? Not looking for new wheels and tires

Drag Pak

Mopar Performance "Super Stock" springs give about 2" of lift, but you would also require the MP "longer shocks"

Iowan

Drag Pak I was thinking the same thing

http://www.summitracing.com/parts/dcc-3412003/overview/
http://www.summitracing.com/parts/dcc-3412002/overview/

These work great, and if memory serves me you can use rear shocks from a 2wd PU, 2" longer. They bolt on your A body and will help with the 4 speed.

I've got them on my Plymouth and it has run 1.41 60ft times with the big 440.

Archer

Guys -

I'm as much of a mopar nut as you are, but I'm honest about it. Drag racing is one thing, but for a road rig or general handling, torsion bars are not the best system. There's reason why coil up grades work (and just about everybody else uses them), and providing additional adjustments is only part of it.

bully -

If you go with SS springs, you may also need to redo the brackets, since on some models the SS spring aren't stock length. "Some" also come with different tensions to a better launch and may result in uneven ride height. Replacement or re-arched spring and new bushing are your best bet.Do your research (talk to a local guys who does mopar suspension) before you buy.

As I said above, the shackles do work, but as a band-aid.

Archer

demetri

Not sure if the term "up grade" applies here. many people buy aftermarket components, and based on their expectation that they would get an improvement, more often than not declare the project "success", without even knowing what improvement they really wanted. The difficulty of recognizing what improvement really is allows these after market manufacturers to continue selling.


Designing a suspension geometry system is a very serious job involving a significant amount of compromises. There is no question that Chrysler did a great job in developing it suspension systems. Replacing that with a complete unknown from the after market is a huge risk, and you may not know what you really got until is too late.


In a vintage Volvo form, we had a guy that claimed that he would sell kits for coil over modifications that would improve over the original suspension. It turned out a complete disaster that generated a difficult and dangerous car to drive.

Iowan

Don't let anyone BS you, SS springs work great on the street and there the same length as your stock A body springs. For year's they have been the standard performance upgrade for your Mopar suspension. They're still selling them because they still work!

Drag Pak

^^^ What he said. The SS springs are developed for the "A Body" and only need "extended" front hangers to go on "B" and "E" bodies. As well, they come in different ratings from 2800lb to 3800 lb car weight. And don't be surprised that the "A" body cars in stock trim are near if not a tad over 3400 lbs.

TVLynn

SS springs !! They will also fit the F body's if you can find the hangers or make your own. I had a set on my 77 RR Volare along with a 8 3/4 rear