Suspension, sway bars, wheel&tire upgrades, help!!!

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sparkie573

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Ok all, so I bought dans 71 408ci scamp.

I am wanting to make it into a fun all around car and handle good. and any info would be great as I am not yet to familliar with a bodies, I have been into cudas.

It currently has. new front stock suspension with polly bushings, ss rear leaf springs relocated to fit 275/60 15" mickeys, kyb shocks all around, home made sub frame connectors that seem well built, stock 318 torsion bars, manual brakes with 11" rear drums and front disks and spindles from a 73 duster mounted on the front side, manual stearing, and no sway bars or mounting tabs.

First on the order list is going to be sway bars probably hellwig tubular 1 1/8 front and 7/8 but I need to know which ones I need due to the spindle and disk swap??? also would any other sway bars be better for the $

second thing that is going to be on my list is some 18" coys wheels and sticky rubber, so what I am needing to know here is if an 8" wheel is as wide as I can go with the spings relocated on the stock wheel tubs and what size tire, what back spacing. And what as far as the front???

then probably going to change the shocks, so bilsteins maybe??

After that I am open to any info and suggestions on the suspension as far as what to do next. I am probably going to stay with stock "style" suspension. thanks ahead, I really appreciate any input.
 
First I would replace the shocks if they are worn with bilsteins, if not worn I would leave them until they are needed

second I would ditch the 318 torsion bars, get .920 or larger bars
third would be the sway bars

If you are familiar with cudas you should already be familiar with the front suspension of an A-body since they are identical in layout the difference are only in the size of the components.
 
Something other than SS springs in the rear, relocated to stock mounting position. Bigger front torsion bars. A FRONT sway bar (contact the manufacturer regarding fit).

A quicker ratio manual steering box helps a lot.
 
hello and welcome from the uk, i have a 68 barracuda 440ci and manual so loooota weight,in my opinion suspention upgrades benefit with additional weight loss, heres what i have so far as i intend to use on track and no straight line doings, 1.18 torsion bars,magnum force tubular uca,strut rods,hellwig sway bar,poly bushes,monroe shox<soon to be spax> flaming river manual steering box,rebuilt colum,battery in trunk,ali inlet/rad/water pump,fiberglass bonnet and wings< 40kg saving just on that> i beefed up my rear springs with a leaf from a fiat ducato van!!! however when funds allow will replace,anyone who says a big block wont handle right never seen me fighting at the wheel! my car went from a death trap 318 barge that lookes like some oil tanker on the high seas to a pretty shap point and go giggle car,just takes the right ingrediants............oh and went with rocket fuel 15" with avon zz3 tyres all round, 225x60 x15, keep same size front to back, 18s look good but in my opinion wont handle anywhere near.i have done this over many years,its always wet here and i have no garage to work in plus i get raped by import duties so its going to be cheeper for you! i reakon im getting there slowly, there is a chap on here autoxcuda and there are video links to him in his cuda on the track, onboard camers, no body roll that i can see, very inspiring as before i saw the vid was at a turning point and it spurred me on no end! good luck, just do a bit at a time and have fun, drive safe
 
Has anyone done much for chassi stiffening?? I am wondering because this 408 seems to be making the car very squirly. when you mash on the gas even in a straight line, you can see the passenger side front dive down from the torque. when you let off to shift and hammer back into it, it jerks side to side... Anyone any info??
i'm pretty sure it is still the stock 318 torsion bars and no sway bars. what would help this the best? or do I need torque boxes and inner fender tube braces? I am just trying to narrow down the cause; either torsion bars, sway bars or chassi?
 
mine originally a /6 so was starting at the bottom, that with the fact my cuda in uk since new doesnt help the body, it hs had new floor sections and parts of the chassis, maybe an idea to get yours up on a ramp and look for any suspect grotty areas,i had the front spring hanger section tear thro my floor!
 
mine originally a /6 so was starting at the bottom, that with the fact my cuda in uk since new doesnt help the body, it hs had new floor sections and parts of the chassis, maybe an idea to get yours up on a ramp and look for any suspect grotty areas,i had the front spring hanger section tear thro my floor!
Good advise!Sounds like the car needs to be given the once over look at all steering components and suspension.Check all mounting areas for rotted areas,mainly control arm mounts(upper and lower)and torsion bar mounts at the rear.Good luck.
 
All of the suspension pieces are new, except the torsion bars. I did a pretty thorough check of the sub when I looked at the car, but you can only see so much without a jack or lift.

Like I said on the other thread, I would get the car up in the air and examine EVERYTHING closely. We already know there may be issues with the torsion bars and steering linkage. I would be afraid to be mashing down hard on a 408 4 speed car that has known issues in the front suspension.
 
I put it up on the lift already and the car looks pretty good. the front suspension seems to be all new with poly bushings, it has subframe connectors, it has ss rear springs relocated under the frame and 275/60 mickey et streets. Just trying to narrow down why it seems to be pulling or twisting under throttle and then let off to shift, or it is when you shift that it un-twists and pulls. maybe the rear end isn't exactly straight, is it the lack of sway bars, or just need heavier torsions? "Brian" the reason that it was sitting on the bumpstops was because he had the torsion bars cranked all the way down. I adjusted them up and it has more suspension travel and isnt on the bumstops anymore. ride heit is 26 1/2 from floor to c of fender wheel lip. im pretty sure that the inner tie rod ends are going to just be that close to the full length headers. Just Trying to get this figured out? hp is 450 and tq is 510. I wouldn't think that is to much hp to twist it under load with frame connectors?
 
What I read is you have no anti sway bar, and old mushy 318 torsion bars in a 450 hp car&#8230; Death wish came to mind. LOL

That sensation of passenger&#8217;s front fender dipping under hard acceleration is just part of the image, the driver&#8217;s side is also lifting. The torque is twisting the front of the car, these cars were designed for less than 300 hp, & 300 ft lb torque from a big old BB.

When chassis twists, and suspension is under sized one ends up with a flopping mess. Envision this: the car is lined up sitting in one position on the frontend rack to factory settings; when accelerating hard, chassis twists temporarily changing every front end setting making for funky handling; upon letting off power the settings once again change requiring more human impute to control the car&#8217;s trajectory&#8230; Sort of like bump steer on steroids; the suspension can&#8217;t do its job if the chassis is constantly deforming, and a soft suspension can&#8217;t cope with the extreme torque demands becoming over taxed.

You need to install additional stiffening under the lower radiator support to tie the front frame rails together, (picture a long low &#8220;U&#8221; under support connecting both rails). At the moment I can&#8217;t locate a vender that I&#8217;ve seen that sells this reinforcement, or just bend up something and weld it on. Also installing torque boxes on all four corners will help stiffen chassis, and further tie it together.

Next is suspension, you need +1 inch torsion bars, 1 1/8 or larger anti sway bar, reinforced lower control arms (it&#8217;s a stiffing plate welded to bottom side of arm). These changes will make the car corner flat, and with chassis stiffened will greatly improve handling close to modern car levels.

Out back I would hold off installing a rear sway bar until all front end upgrades are made, and you have driven the car for a while to assess its new handling characteristics. A Bodies tend to be tail happy, and rear sway bar can exacerbate oversteer depending on rear spring and tire choice. SS springs are a drag race item where spring has a higher arch that cocks the car to handle the torque load under WOT; a good thing for drag racing, but perhaps not ideal for road handling. A lot of folks use them on the street, but I don&#8217;t believe they offer the best street manners and are a trade-off for track performance.

You have to decide if you want a drag queen, or a good handling road machine that will perhaps give up a wee bit at the track but still go like stink.

You may find that six lief stock ride height rear springs such as stock Formula S Cuda used may provide better road handling. Stock ride height will settle down a tail happy car. As the rear end of these cars is lifted, oversteer becomes more of an issue.
 
He also has poly-loc motor mounts and a torque strap, I think that those are great additions, but they also transfer a lot of that torque straight to the front sub frame.

I like the idea of stiffening the core support and plan on doing this as mine has been cut to fit a larger radiator. Dillinger is the member I believe that makes and sells these for A bodies. Also going to a larger torsion bar and adding a front sway bar will do wonders for the handling of this or any A body.

I'm glad to hear that you got the car up off of the bump stops and that's a bummer about the tie rod end being so close to the header. I checked it and it didn't look like it was hitting but it was awfully close.
 
yeah the tie rods are like right there maybe an 1/8 away but they do clear.

As for the rest. I am going to get off of some $ and order some stuff. I was just trying to narrow it down to mostly the torsion bars or chassi flex but I'll take care of it all at once. thanks for the lower radiator suport stiffening idea, I had totally forgotten about doing that.

I ordered from pst today; 1.03" torsion bars, and Lca stiffening plates. I'm probably going to order hellwig front and rear tubular sway bars tomorrow. I will be making some tube inner fender braces also. for now I am going to stay with the kyb shocks and stock tie rods since dan had just replaced all of that, although I may put some hardened sleaves to get rid of the stock ones. The ss rear leaves will probably stay for now, I'm sure I'll end up changing them but probably last.

If anyone has a pic of a lower rediator brace on an a body I can probably fab one up?

I will also probably put the torque boxes in if anyone knows where i can get them? Any other suggestions or info appreciated.
 
Here's a thread about the XV Motorsports radiator brace.

Here is a link to the brace itself.

Lower%20Rad(1)%20-%20Web%20Large%20Photo1.jpg
 
do the weld in UScartool subframe connectors. i have one of their radiator support braces i didn't use if you are interested. i didn't need it since it have an alter-k. upgrade the frontend,and if you have the cash,go ahead and do a street lynx rear kit.
 
The car should go straight under acceleration, period.. the problem is most likely in the rear of the car, The rear end MUST be straight with the centerline of the chassis. A sway bar and/or bigger torsion bars are a waste of time if the rear is out of square. LOTS of drag cars run 10s, and over 120 mph with 6 cyl torsion bars and NO swaybar.. Beefing up the chassis is a good idea, but it AINT your problem
 
Has anyone done much for chassi stiffening?? I am wondering because this 408 seems to be making the car very squirly. when you mash on the gas even in a straight line, you can see the passenger side front dive down from the torque. when you let off to shift and hammer back into it, it jerks side to side... Anyone any info??
i'm pretty sure it is still the stock 318 torsion bars and no sway bars. what would help this the best? or do I need torque boxes and inner fender tube braces? I am just trying to narrow down the cause; either torsion bars, sway bars or chassi?
This is what I am refering to
 
yeah the tie rods are like right there maybe an 1/8 away but they do clear.

As for the rest. I am going to get off of some $ and order some stuff. I was just trying to narrow it down to mostly the torsion bars or chassi flex but I'll take care of it all at once. thanks for the lower radiator suport stiffening idea, I had totally forgotten about doing that.

I ordered from pst today; 1.03" torsion bars, and Lca stiffening plates. I'm probably going to order hellwig front and rear tubular sway bars tomorrow. I will be making some tube inner fender braces also. for now I am going to stay with the kyb shocks and stock tie rods since dan had just replaced all of that, although I may put some hardened sleaves to get rid of the stock ones. The ss rear leaves will probably stay for now, I'm sure I'll end up changing them but probably last.

If anyone has a pic of a lower rediator brace on an a body I can probably fab one up?

I will also probably put the torque boxes in if anyone knows where i can get them? Any other suggestions or info appreciated.

Subframe connectors should be plenty IF you have a such a problem with the chassis flexing and the car won't go straight when you slam the gears.

Adding a rear sway bar with those stiff super stock springs might make the car tail happy.

Might consider 17" rims in front if want some sidewall on the tires. The thinner the sidewall the quicker and twitchy'er the car reacts. Look at 245 wide front tires with 5.5" backspace.
 
X2 on the subframe connectors 1st and while you are at it under the Car, do the Torque Boxes also, check your rear spring and Shackel Bushings. (My 2 Cents). Keep us Posted. HOW ABOUT PICS! Good Luck.:happy1:
 
He has sub-frame connectors.


He's got some item that needs repair/adjustment or he's just slamming the gears on a crappy surface. Like on a street that's dirty with winter debris, drive off from dirt roads, has a lot of road camber so the streets angled.
 
I am waiting untill I get all of my parts and then I will be tearing down the front to swap the spindles around so they are mounted in the rear as well as check everything out and adding some offset uca bushings. I got my sway bars, lca plates and hd tie rod sleeves in. still waiting on the torsion bars.
baddart is fabing up me a lower radiator support and inner fender supports. And I will be fabing up and installing some torque boxes. I checked out the rear and all the bushings seem ok. I'll have to take it in for an allignment so I'll have them check the the rear to make sure the rear is straight.

Hopefully after all of that It won't pull and will go like skink even around corners.
Has anyone tried a triangulated shock brace going from shock to shock back to the firewall? seems like they would stiffen things up a bit.

any more info would be great.

Right now the car is taking up my buddies lift while I get the shift box and rods figured out and fixed. Then to fix some wiring. and then some interior insulation. and so on and so on and so on. lots of info on this site.
 
Sounds like you are making good progress! Keep us informed on how things work out?
 
had gotten all of my parts in and finally got some time to take the car over to the shop, put on the lift and tear the suspension down. after checking everything out I found that the upper and lower ball joints were new and the strut rod bushings were new as well as the inner and outer tie rod ends and idler arm and pitman arm as well as the kyb gas adjust shocks....
What was not new however were the upper control arm bushings and the lower control arm bushing, As they looked 1971 patina. I guess the previous owner had no way to replace them... So, in went my new fender well braces from baddart, 1.03 torsion bars, lower control arm plates, heavy duty tie rod sleeves all from pst. then replaced my upper control arms with the moog offset bushings and moog lower control arm bushings. I mounted the front hellwig sway bar and then followed that up with a good coat of undercoat on everything. And then some new inner and outer wheel bearings.

Sorry no pictures as we were kinda thrashing on it. I set and adjusted the height at 25 1/2 from the floor to c of the wheel well. I am taking it in for a full alignment tomorrow and we'll see how she drives after that... Then I will put the rear sway bar in possibly and the lower radiator support. I'll try and get some pictures in also... Any input would be great. Oh and what should I be looking to try and get for caster, camber and toe in? I am thinking somewhere around 3-4 pos caster, 1/2 degree neg camber, and 1/8 or so toe in.?
 
Hello. Please help me.
I have a question...
It put off the front subframe (K-frame) and arms when the engine is in the car?
 
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