1971 Duster Handeling

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I have the stage 2 qa 1 suspension and a Hotchkiss front sway bar, and a new borgenson steering box. Would be interested to know besides the chin spoiler whats done to the valiant? That spoiler dosent look that bad actually. So basically no bone stock mopar besides a gen 3 b body can do140 to 150?

They can do it. With right gearing and motor.

But driving it is not going to be a walk in the park like modern cars.

Still haven't answered some basic question on what YOUR current setup is that you have issue with.

  1. What tire size, brand, and model are you running?
  2. what is you front torsion bar size
  3. what rear spring do you have
  4. what shocks do you have
  5. what are your alignment specs
 
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I have the stage 2 qa 1 suspension and a Hotchkiss front sway bar, and a new borgenson steering box. Would be interested to know besides the chin spoiler whats done to the valiant? That spoiler dosent look that bad actually. So basically no bone stock mopar besides a gen 3 b body can do140 to 150?

The "red brick" Valiant is pretty heavily modified in the suspension department. When it was built is was wild, although now you can pretty easily just buy everything that was on it. There's a list of it's specs here
mopar handling

I would add that just because the Red Brick hit 160 mph doesn't mean that it wasn't front end light when it did it. You might reach out to @lilcuda, he was the most recent owner of the 'brick that I recall although I'm not sure he still has the car.

The other thing is the aero for a Valiant is different. From an "added" point of view it just has the air dam, but from a bodywork standpoint the Valiant has less grille opening and less grille inset. Sure, it isn't much, but every bit of air that goes through the grille and into the engine compartment leaves by going under the car. That's lift. And every bit of hood that overhangs the grille is a wing.

The Charger 500's that were mentioned earlier had pretty subtle modifications that improved their aero quite a bit. The grilles weren't inset as far, and the rear window glass was flushed in to the rear of the car. Those differences are small compared to a regular '68-70 Charger, but the aero difference they make is substantial.

Does anyone think this will help much?


https://www.spoilersbyrandy.com/70-73-duster

The Spoilers by Randy spoilers are pretty small. For awhile he made a taller one, in fact if you look at the pictures on the Duster page I think the black car has a smaller spoiler than the red car. Needless to say you want as large as you can tolerate.

Another option is a '67 Camaro spoiler. You can get an ABS version for $30. 1967 CHEVROLET CAMARO OER 3916673 OER Injection-Molded Front Spoilers | Summit Racing

Because it's ABS you will want to support from behind, you can probably modify the stock hardware 1967 CHEVROLET CAMARO Goodmark GMK402003667S Goodmark Front Spoiler Mounting Braces and Components | Summit Racing

I run the OER spoiler on my Duster (Demon clone). I don't have a picture but I have a support rod that goes from the middle of the spoiler back to the lower radiator support where the K frame brace mounts.

IMG_9932.jpeg


845e06f8-239e-4f7c-80ea-2a32ef2ce9f7-jpeg-jpg.jpg
 
There's also the DC style front spoiler for the Dusters, although I can't find anyone selling a replica at the moment
9392825212_4ef18a4f70_o copy.jpg

And the rear DC spoiler, which is being sold currently. I have one from this seller, it's a pretty accurate recreation...
70-76 Plymouth Duster and Dart Sport Showcars Rear Spoiler | eBay
9392824540_1a79027418_o copy.jpg



And for a more air dam version there's this...
Awesome A-body air dam for under $30!
air-dam-1-jpg.jpg


It's off a Ford Ranger. This is obviously a Dart but since it's mounted underneath it should work about the same on a Duster. Probably do a better job than the Camaro spoiler since it has better coverage. Not sure it looks as good but if what you're after is aerodynamics it's probably the better choice.
 
There's also the DC style front spoiler for the Dusters, although I can't find anyone selling a replica at the moment
View attachment 1715910421
And the rear DC spoiler, which is being sold currently. I have one from this seller, it's a pretty accurate recreation...
70-76 Plymouth Duster and Dart Sport Showcars Rear Spoiler | eBay
View attachment 1715910420


And for a more air dam version there's this...
Awesome A-body air dam for under $30!
View attachment 1715910425

It's off a Ford Ranger. This is obviously a Dart but since it's mounted underneath it should work about the same on a Duster. Probably do a better job than the Camaro spoiler since it has better coverage. Not sure it looks as good but if what you're after is aerodynamics it's probably the better choice.
I did the Ranger one. And added a thin aluminum splitter. I need to get pics.
 
I did the Ranger one. And added a thin aluminum splitter. I need to get pics.

Nice, let's see some pictures!

Honestly I think these cars look way better with some kind of a spoiler or air dam up front. Otherwise you see the K frame, sway bar, etc hanging down. The spoilers or dams that hide all that stuff just clean things up visually. And hey, a little less air going under the car isn't bad either.
 
OP seems really resistant to explain why and where he wants to go so fast.

1 hmmmm.jpeg
 
Nice, let's see some pictures!

Honestly I think these cars look way better with some kind of a spoiler or air dam up front. Otherwise you see the K frame, sway bar, etc hanging down. The spoilers or dams that hide all that stuff just clean things up visually. And hey, a little less air going under the car isn't bad either.
I agree if anyone knows of something they make now that's better than Randy's that will fit with no modification. Otherwise I think I will try his. Do better brakes and wheel bearings and lower front end and maybe stiffer torsion bars than qa 1 offers that's gotta help I would think.
 
OP seems really resistant to explain why and where he wants to go so fast.

View attachment 1715910440

Right?

I agree if anyone knows of something they make now that's better than Randy's that will fit with no modification. Otherwise I think I will try his. Do better brakes and wheel bearings and lower front end and maybe stiffer torsion bars than qa 1 offers that's gotta help I would think.

The Camaro spoiler is almost identical to Randy's except taller and with slightly more of a "V" shape (less straight). You should be able to mount it to your lower radiator support and bumper without any modifications to the car, it will go smoother if you have a heat gun to use on the spoiler but it's not mandatory.

As far as what else will help you, you're keeping us far too much in the dark for anyone to have a good idea of what to suggest. There are people here that take their cars on road courses at the kinds of speeds you're talking about, but unless you give us a better idea of how your car is set up and what you're actually planning on doing there isn't much anyone can say.

And what QA1 stuff do you have? Because right now a Stage II QA1 system is a full coilover conversion. Clearly you don't have that. But even a Stage I system has upper and lower tubular control arms with a tubular K, so I'm curious what you'll do to the "lower front end" that will help. Did you install all new suspension and leave the old wheel bearings?

You really aren't giving us much to work with. If you started by answering autoxcuda's questions from post #27 it would be a good start.
 
Nice, let's see some pictures!

Honestly I think these cars look way better with some kind of a spoiler or air dam up front. Otherwise you see the K frame, sway bar, etc hanging down. The spoilers or dams that hide all that stuff just clean things up visually. And hey, a little less air going under the car isn't bad either.
mine is a beaker so it’s a bit different. I’ll get some pics one evening this week. Car currently isn’t at home with me
 
This is like pissing into the wind. The op probably has no idea what he has cause he didn’t do any of the work. Probably doesn’t know what the parts are called. Asking about different torsion bars is a big clue right there. Won’t answer any questions because he has no knowledge of anything. Kim
 
Lee (Lilcuda) sold the Valiant a while ago (3-4 years give or take).

Some Chrysler 300 letter cars were good for 140. 1969 Polara pursuit car was clocked at 149.
 
Lee (Lilcuda) sold the Valiant a while ago (3-4 years give or take).

Some Chrysler 300 letter cars were good for 140. 1969 Polara pursuit car was clocked at 149.

Yeah I thought I heard he'd sold it. But I have a hard time keeping track, I know there's a member here that bought Tom K's Valiant too (the purple one built for autoX) after he sold it. That one might have changed hands again too.
 
Some great suggestions here!
My favorite mods are block off as much air as possible thru the grille, at that speed you won't need a big opening. Adjust the rear edge of the hood so air can escape. Lower the nose, now this will reduce caster.
So you'll have to do some mods to get the caster back to positive. Make sure wheels aren't toed out!
 
Right?



The Camaro spoiler is almost identical to Randy's except taller and with slightly more of a "V" shape (less straight). You should be able to mount it to your lower radiator support and bumper without any modifications to the car, it will go smoother if you have a heat gun to use on the spoiler but it's not mandatory.

As far as what else will help you, you're keeping us far too much in the dark for anyone to have a good idea of what to suggest. There are people here that take their cars on road courses at the kinds of speeds you're talking about, but unless you give us a better idea of how your car is set up and what you're actually planning on doing there isn't much anyone can say.

And what QA1 stuff do you have? Because right now a Stage II QA1 system is a full coilover conversion. Clearly you don't have that. But even a Stage I system has upper and lower tubular control arms with a tubular K, so I'm curious what you'll do to the "lower front end" that will help. Did you install all new suspension and leave the old wheel bearings?

You really aren't giving us much to work with. If you started by answering autoxcuda's questions from post #27 it would be a good start.
I have level 1 handling kit from qa 1 and front sway bar from Hotchkiss and mopar competition rear springs. Only difference between racing suspension kit and handling is the shocks I don't know If they would make any difference. The kit seemed to make no difference on top end handling at all. Running bf Goodrich radial tires on stock front rallye wheels. Don't know what else you would like to know?
 
There's also the DC style front spoiler for the Dusters, although I can't find anyone selling a replica at the moment
View attachment 1715910421
And the rear DC spoiler, which is being sold currently. I have one from this seller, it's a pretty accurate recreation...
70-76 Plymouth Duster and Dart Sport Showcars Rear Spoiler | eBay
View attachment 1715910420


And for a more air dam version there's this...
Awesome A-body air dam for under $30!
View attachment 1715910425

It's off a Ford Ranger. This is obviously a Dart but since it's mounted underneath it should work about the same on a Duster. Probably do a better job than the Camaro spoiler since it has better coverage. Not sure it looks as good but if what you're after is aerodynamics it's probably the better choice.
I like the DC spoiler or Randy's the best do you think Randy's will do anything at all or is it looks only?
 
The "red brick" Valiant is pretty heavily modified in the suspension department. When it was built is was wild, although now you can pretty easily just buy everything that was on it. There's a list of it's specs here
mopar handling

I would add that just because the Red Brick hit 160 mph doesn't mean that it wasn't front end light when it did it. You might reach out to @lilcuda, he was the most recent owner of the 'brick that I recall although I'm not sure he still has the car.

The other thing is the aero for a Valiant is different. From an "added" point of view it just has the air dam, but from a bodywork standpoint the Valiant has less grille opening and less grille inset. Sure, it isn't much, but every bit of air that goes through the grille and into the engine compartment leaves by going under the car. That's lift. And every bit of hood that overhangs the grille is a wing.

The Charger 500's that were mentioned earlier had pretty subtle modifications that improved their aero quite a bit. The grilles weren't inset as far, and the rear window glass was flushed in to the rear of the car. Those differences are small compared to a regular '68-70 Charger, but the aero difference they make is substantial.



The Spoilers by Randy spoilers are pretty small. For awhile he made a taller one, in fact if you look at the pictures on the Duster page I think the black car has a smaller spoiler than the red car. Needless to say you want as large as you can tolerate.

Another option is a '67 Camaro spoiler. You can get an ABS version for $30. 1967 CHEVROLET CAMARO OER 3916673 OER Injection-Molded Front Spoilers | Summit Racing

Because it's ABS you will want to support from behind, you can probably modify the stock hardware 1967 CHEVROLET CAMARO Goodmark GMK402003667S Goodmark Front Spoiler Mounting Braces and Components | Summit Racing

I run the OER spoiler on my Duster (Demon clone). I don't have a picture but I have a support rod that goes from the middle of the spoiler back to the lower radiator support where the K frame brace mounts.

View attachment 1715910411

View attachment 1715910414
Would also consider this one

Screenshot_20220419-212148_eBay.jpg
 
I have level 1 handling kit from qa 1 and front sway bar from Hotchkiss and mopar competition rear springs. Only difference between racing suspension kit and handling is the shocks I don't know If they would make any difference. The kit seemed to make no difference on top end handling at all. Running bf Goodrich radial tires on stock front rallye wheels. Don't know what else you would like to know?

Your actual alignment specs, since those are the recommended specs you posted and not your actual numbers since no shop would tell you your caster is "3° to 5°". Also, if you want to be doing 120+ you'll want more aggressive alignment numbers than what's there.

But we're getting somewhere. You changed all that suspension out and still have the same issue? So, that would indicate it's probably not the suspension- so aero, or something else...


Holy crap Batman. See, this is why we asked about how your car is set up.

You're running "S" rated BFG hockey pucks at 120 mph? Those tires are only rated for 112 mph. You think you're going to get good performance out of those at 120? Not a chance. Those tires probably wouldn't even make it to 150, and there's nothing like an overheated tire blow out at 120+ to make life really entertaining.

I'm sure you still have other issues, but those tires for those speeds are a really, really bad idea.

I like the DC spoiler or Randy's the best do you think Randy's will do anything at all or is it looks only?

The Randy's spoiler will do something, like I said, any air it keeps from going under the car is a win. But when you call and order it, ask if he still makes the "tall" version. It would be more beneficial for you.

Would also consider this one

View attachment 1715910692

That one is a copy of the DC front spoiler. It should work, but you're doing to need to add some bracing because all it appears to be is a thin layer of fiberglass. You'll need to back it up to keep it from just folding over at 100+.
 
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Need Z rate 150 mph tires

Need alignment spec sheet to what is on your car
 
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