1971 Duster Handeling

[Kern Dog]

205 70 14 bf Goodrich radial ta tires

Really ??

Come on, man....you're messing with us here aren't you?

 

[snowcrane2005]

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.



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.



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+.

I will get the actual alignment specs as I did not do it myself of of course. When i put competition springs and big rear tires it raised rear of car and i raised the front up to compensate so I'm sure this is all compounding the problem. Does anyone have any suggestions on good tires I can get that would be rated for that speed and would fit on stock Rims? And do you think this is much difference between a tall one from randy and the DC spoiler? I imagine the DC spoiler would work better since it is mounted to bumper. Also with the DC I should still probably look at lowering the car if I can at all correct? How high do you have your car off the ground from the bottom of the front spoiler?

 

[dukeboy440]

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.



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.



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+.

hockey pucks?! Hell them tires are like mini CDs.

I will get the actual alignment specs as I did not do it myself of of course. When i put competition springs and big rear tires it raised rear of car and i raised the front up to compensate so I'm sure this is all compounding the problem. Does anyone have any suggestions on good tires I can get that would be rated for that speed and would fit on stock Rims? And do you think this is much difference between a tall one from randy and the DC spoiler? I imagine the DC spoiler would work better since it is mounted to bumper. Also with the DC I should still probably look at lowering the car if I can at all correct? How high do you have your car off the ground from the bottom of the front spoiler?

lower the front, drop the back with blocks, but most importantly, you need better than stock rims. An 7-9 inch wide tire isn’t gonna do you any good. You can get “stock” looking rims that are wider and would allow you to run a 10-12 inch wide tire. I know @72bluNblu is running 18s on his and has fit 275s.

basically, based on what we know now, you’re trying to do make your top speed higher without changing the car from looking and that’s not gonna be possible. You need to tackle tires, aero(not only the front air dam, but I’d be smoothing things out underneath and sealing up seams), suspension AND brakes, stock brakes will be sketchy trying to stop from 150 mph, and lastly, I would HIGHLY recommend interior passenger safety measures.

 

[dukeboy440]

Here’s the other question, is this a stock engine and what engine? Stock drive train? Stock cooling system?

 

[snowcrane2005]

Here’s the other question, is this a stock engine and what engine? Stock drive train? Stock cooling system?

340 engine stroked hemi radiator car cools excellent passon 5 speed McCloud dual friction clutch upgraded drive shaft and rebuilt 8 and 3/4 489 case all everything is built to hold 700 hp besides rear-end which will probably only hold 500.

 

[dukeboy440]

340 engine stroked hemi radiator car cools excellent passon 5 speed McCloud dual friction clutch upgraded drive shaft and rebuilt 8 and 3/4 489 case all everything is built to hold 700 hp besides rear-end which will probably only hold 500.

well that’s a start.
And it’s built for high sustained RPMs? Plus sustained speeds of that nature equate to high drive train heats.
Granted it sounds like you’re gonna do this on some highway somewhere so I don’t know how long that sustained speed will actually be

 

[snowcrane2005]

well that’s a start.
And it’s built for high sustained RPMs? Plus sustained speeds of that nature equate to high drive train heats.
Granted it sounds like you’re gonna do this on some highway somewhere so I don’t know how long that sustained speed will actually be

Not Long distances a really would just like to be able to sustain 130 to 140 for a mile or so and maybe touch 150 not looking for 160 or anything crazy like that!

 

[66fs]

14 in rallye rims will work, the trick will be finding tires. Go to tire rack and look at 195/60/14 tires with a speed rating H, 130 mph sustained speed, or above. These are the only ones I could find, other than race only, to work with 14 in wheels.

 

[sccachallenger]

If you're at all handy with tools, you can fabricate a front spoiler. I did it on my '72 Challenger.
Make one out of cardboard, cut and tape 'till you like the fit then transfer to flat piece of plywood. Figuring out mounting brackets will be time-consuming, but do-able.
Make room for brake ducts in case you want to add some later. Paint it satin black and it'll look fine on the car.

 

[66fs]

Need Z rate 150 mph tires

Need alignment spec sheet to what is on your car

If you really want to run 150, then I'd have to agree with autoxcuda, Z or W speed rated tires. You definitely do not want a front tire coming apart at 150 mph. That is serious speed, not to be taken lightly.

 

[autoxcuda]

I will get the actual alignment specs as I did not do it myself of of course. When i put competition springs and big rear tires it raised rear of car and i raised the front up to compensate so I'm sure this is all compounding the problem. Does anyone have any suggestions on good tires I can get that would be rated for that speed and would fit on stock Rims? And do you think this is much difference between a tall one from randy and the DC spoiler? I imagine the DC spoiler would work better since it is mounted to bumper. Also with the DC I should still probably look at lowering the car if I can at all correct? How high do you have your car off the ground from the bottom of the front spoiler?

what's the rear tire size and rim size?

sounds like front end is catching a bunch of air and raising car in front those speeds

again do you have stock size front torsion bars?

 

[mbaird]

Did 145 in my 70 Charger but boy that thing was getting light ! Wouldnt do it again .

OP....Whats the fastest you have ever been in a car ? Things are going by awefully fast at those speeds.
We have a unlimited speed road run every year up in Sun Valley with speeds up to 260 mph . Those are the Bugatti Veyrons ... 911 Turbos will hit 205ish , a few Mclarens running 220ish , 1 Mustang and a few Corvettes exceeding 200. Pretty cool event .
Those Bugattis sound like jets approaching ... Wooosh !!!!!!

 

[mbaird]

Here is a link to a video of last years event.
Sun Valley Tour de Force - Visit Sun Valley

 

[snowcrane2005]

Here is a link to a video of last years event.
Sun Valley Tour de Force - Visit Sun Valley

I can't even get it to 120 and hold it so I know that's not right. Qa 1 is positive it's alignment there saying 130 shouldn't be that difficult with there handling kit underneath the car. I'm going to check with the alignment place. Wish I knew of somewhere good in Minnesota to take it?

 

[mbaird]

I can't even get it to 120 and hold it so I know that's not right. Qa 1 is positive it's alignment there saying 130 shouldn't be that difficult with there handling kit underneath the car. I'm going to check with the alignment place. Wish I knew of somewhere good in Minnesota to take it?

I was in between Hutchinson and Litchfield when I hit 145.

 

[mbaird]

There is a FABO member that is restoring a Mr Norms GSS car that is in MN and owns a chain of tire stores... he should have a good alignment guy ... I will try to remember his name. He posts a lot for NOS wanted items and cost is no concern . Cant wait to see this car !

 

[dukeboy440]

I can't even get it to 120 and hold it so I know that's not right. Qa 1 is positive it's alignment there saying 130 shouldn't be that difficult with there handling kit underneath the car. I'm going to check with the alignment place. Wish I knew of somewhere good in Minnesota to take it?

They’re lying to you.

 

[diymirage]

easiest way to get that duster to hit 150

[FOR SALE] - NOS A-body dash cluster with Kilometer speedo. $500 obo | For A Bodies Only Mopar Forum

 

[Kern Dog]

Wish I knew of somewhere good in Minnesota to take it?

Finally the OP mentions where he is and where he wants to drive this car.
It really sounds like the OP knows very little about cars and driving fast, yet wants to jump right into the big leagues.
Inexperience can get not only you killed, but others around you.
I'm all for freedom to do dumb stuff. Have at it but don't try this stuff on a busy public road.
Are you looking to do solo runs in competition? Are you looking at wide open spaces in Montana or Wyoming?
Why is 150 mph so important?

 

[65TerrorCuda]

Salt flats car? Then I'd say go for it. Otherwise you could rent a fast car to get it out of your system. It's really not that amazing to go fast and run something over at 125

 

[mbaird]

Finally the OP mentions where he is and where he wants to drive this car.
It really sounds like the OP knows very little about cars and driving fast, yet wants to jump right into the big leagues.
Inexperience can get not only you killed, but others around you.
I'm all for freedom to do dumb stuff. Have at it but don't try this stuff on a busy public road.
Are you looking to do solo runs in competition? Are you looking at wide open spaces in Montana or Wyoming?
Why is 150 mph so important?

I had an F150 pass me like I was standing still this morning on the freeway ... I was doing about 75-80 mph at the time . He was weaving thru traffic . Pissed me off ! This happens several times per day when I take the freeway . I saw the name of his company on the side of the truck and called them . I told them next time I call the state police and have them pay a visit . Its so bad out here now with all the out of staters ( Californians) that I wont ride my motorcycle on the freeway ! I have never feared for my life while riding my bike .
Im waiting 5 years then moving to California... I figure all their assholes will have moved to Idaho by then .lol

 

[Mattax]

what's the rear tire size and rim size?

sounds like front end is catching a bunch of air and raising car in front those speeds

again do you have stock size front torsion bars?

Egzactly. As you know when one looks at real road race cars, they all had their bodies as low as possible.
Same rake can help, but if air is getting underneath, thats a problem.
If the suspension has been raised, that's going to hurt geometries for stability as well as roll center heights.

 

[mbaird]

Salt flats car? Then I'd say go for it. Otherwise you could rent a fast car to get it out of your system. It's really not that amazing to go fast and run something over at 125

I sold high end cars for 25 years and have driven most every fast car available. Supercars are so stable and handle so well that 150 is almost boring.
Its not a matter of losing control that will kill you .. its that other drivers cant anticipate your intended manuevers and collisions occur.

 

[dukeboy440]

Egzactly. As you know when one looks at real road race cars, they all had their bodies as low as possible.
Same rake can help, but if air is getting underneath, thats a problem.
If the suspension has been raised, that's going to hurt geometries for stability as well as roll center heights.

Which is why mine has 2 inch forged drip spindles and have the coil overs set as low as I can go.

 

[72bluNblu]

Which is why mine has 2 inch forged drip spindles and have the coil overs set as low as I can go.

You can get just as low with torsion bars and standard spindles. The backside of the inner fender is the limit in the front. With my current set up, at full suspension compression there’s only 13” from the spindle to the bottom of that inner fender, which means a 26” tall tire would hit. Gotta add clearance to the inner fenders after that.

72BBSwinger added clearance on his…