Rear sway bar for 1964 plymouth valiant

[64whiteghost]

Whatsup guys.

Im running a QA1 1 1/4 front sway bar. Should I go with a rear 3/4s or 7/8s sway bar ?

I will be running a 450hp 340. With a 4 speed btw

 

[Kern Dog]

There are variables to consider.
On the surface, I'd advise against the larger bar based on the assumption that all else being equal with both rear bars aside from the diameter, the larger bar will likely induce a strong OVERsteer condition. Great for drifting, terrible for regular street driving.
The variables include the length of the lever arms, the overall shape, the material used for the bars and the methods that they are attached.
A 7/8" bar with 10" lever arms may not be as stiff as a 3/4" bar with 9" lever arms.

 

[junkyardhero]

a large rear swaybar can tend toward oversteer. even more so in a system that's not thoroughly balanced.

a 7/8" bar is absolutely massive, especially if it's solid. i'd go smaller, much smaller. depending on the design of your rear springs you may not even need a rear bar.

 

[64whiteghost]

There are variables to consider.
On the surface, I'd advise against the larger bar based on the assumption that all else being equal with both rear bars aside from the diameter, the larger bar will likely induce a strong OVERsteer condition. Great for drifting, terrible for regular street driving.
The variables include the length of the lever arms, the overall shape, the material used for the bars and the methods that they are attached.
A 7/8" bar with 10" lever arms may not be as stiff as a 3/4" bar with 9" lever arms.

View attachment 1716099786

Thank you !

 

[64whiteghost]

a large rear swaybar can tend toward oversteer. even more so in a system that's not thoroughly balanced.

a 7/8" bar is absolutely massive, especially if it's solid. i'd go smaller, much smaller. depending on the design of your rear springs you may not even need a rear bar.

Thank you

I got the mopar performance leaf springs
Mopar Performance P4120863: Competition Leaf Spring A-Body - JEGS

 

[junkyardhero]

Thank you

I got the mopar performance leaf springs
Mopar Performance P4120863: Competition Leaf Spring A-Body - JEGS

those are "SS springs", designed for drag racing. they are not ideal for handling because they're too stiff-- the spring rate is much higher than what you would want for a good handling street car and pairing that stiffness with a rear bar will make the car really tail happy (oversteer).

they also have a considerably higher ride height.

have you installed them yet? because you may not like the ride height they have.

can they work, sure. but they may not be optimal for what you're trying to achieve and i definitely wouldn't run a rear bar with them.

 

[64whiteghost]

those are "SS springs", designed for drag racing. they are not ideal for handling because they're too stiff-- the spring rate is much higher than what you would want for a good handling street car and pairing that stiffness with a rear bar will make the car really tail happy (oversteer).

they also have a considerably higher ride height.

have you installed them yet? because you may not like the ride height they have.

can they work, sure. but they may not be optimal for what you're trying to achieve and i definitely wouldn't run a rear bar with them.

Thank you for your response

I have not installed them yet. I just assumed that they were the right fit. Which ones should I get for my application ?

How much ride height do they give in the back ?

 

[junkyardhero]

Thank you for your response

I have not installed them yet. I just assumed that they were the right fit. Which ones should I get for my application ?

How much ride height do they give in the back ?

there's a lot of factors at play here. how do you want the car to sit? how much height do need to clear whatever wheel & tire combo you have? how do you want the car to perform, what are your expectations for ride quality, and how do you plan to drive it?

i can't just say: oh, install [blank company's] OE XHD +1" 4 leaf and you'll be great because i don't know what all you got cooking.

i will say that an OE style formula S/HD or XHD is probably at or near the spring rate that you'd want to run for a street and sometimes autox car. arch height will be dictated by the look you want and whatever limitations your wheel/tire combo is.

but, you can address height with adjustable spring hangers-- to a certain degree-- without jacking up handling. i would strongly recommend against running anything more than 1" block to get where you need, and even then, i am loathe to suggest blocks.

all of this is to say, the SS springs are not the answer unless the expectation is mainly straight line performance.

 

[clifftt]

Suggest you contact Espo Springs and run by them what your goal is. They used to, hopefully still, sell de-arched springs to keep the back end ride height or lower the back end, which is what you want if you are trying to lower the center of gravity and make your car handle. Junkyardhero is correct, those SS bars will hike up the back end, used for weight load transfer when launching your car for a drag race. You can have one or the other but not both ... make a pick, what's your goal???

 

[clifftt]

Sorry, here's a link to them...
leaf-spring.htm

 

[64whiteghost]

there's a lot of factors at play here. how do you want the car to sit? how much height do need to clear whatever wheel & tire combo you have? how do you want the car to perform, what are your expectations for ride quality, and how do you plan to drive it?

i can't just say: oh, install [blank company's] OE XHD +1" 4 leaf and you'll be great because i don't know what all you got cooking.

i will say that an OE style formula S/HD or XHD is probably at or near the spring rate that you'd want to run for a street and sometimes autox car. arch height will be dictated by the look you want and whatever limitations your wheel/tire combo is.

but, you can address height with adjustable spring hangers-- to a certain degree-- without jacking up handling. i would strongly recommend against running anything more than 1" block to get where you need, and even then, i am loathe to suggest blocks.

all of this is to say, the SS springs are not the answer unless the expectation is mainly straight line performance.

Thank you for responding

Here is the set up Iam building

1964 Plymouth Valiant No Post

Motor: 1969 340 bored .30 over with forged pistons. Heads will be ported and polished, Crane cams Roller Rockers. Edelbrock Performer (Intake will be port matched). Cam will be custom .550 lift. TTI Long tube headers. Full MSD Ignition. Holley electrical pump: Goal is 450hp

Transmission: A833 4 speed

Rear end: 8 3/4 3:73 Gears with Posi

Front Suspension: QA1 Upper and Lower control arms, QA1 Front Sway bar. QA1 single adjustable shocks. Dr Diff 11.75 slotted Disc brake power brake kit.

Front tires: Wheel Vintiques 63 Series O.E. Chrysler Black Wheels: 225/60/15 Big bolt

Rear suspension: Mopar Performance SS Leaf springs. QA1 rear single adjustable shocks. 11 inch drum brakes big bolt

Rear wheels: Wheel Vintiques 63 Series O.E. Chrysler Black Wheels: 245/60/15 big bolt

The car will be a weekend warrior to go to car shows and enjoy on the weekends. Ive always wanted a little street beast and thats my goal. For cruising I have the 1966 Plymouth valiant convertible 273 4 speed.

 

[junkyardhero]

how do you want the car to sit? low? super low? stock-ish? a little rake with the *** up? how much wheel/tire do you want to show?

have you test fit the rims and tires? do you *need* it to sit at a specific height so that the tires don't rub anywhere?

i know this all seems very particular and overwrought, but all of this has a bearing on choosing springs that will work.

as a somewhat educated guess, if you're not fouling the tires anywhere in the wheel wells and you're okay with it sitting at slightly lower than stock height i'd order up these: 1967-1976 Dodge A-Body Geometry Corrected Leaf Springs

the main reason is that i know they'll be decent quality, they come with the bushings and new hardware, and they're listed at 130 in/lb rate which is about what you want for street handling and to compliment the front t-bars. they also have a half leaf front so the forward section will be stiffer and you may not need a swaybar.

but as mentioned above, you could call espo and talk to them and see what they have to offer and that would give you another option.

 

[64whiteghost]

how do you want the car to sit? low? super low? stock-ish? a little rake with the *** up? how much wheel/tire do you want to show?

have you test fit the rims and tires? do you *need* it to sit at a specific height so that the tires don't rub anywhere?

i know this all seems very particular and overwrought, but all of this has a bearing on choosing springs that will work.

as a somewhat educated guess, if you're not fouling the tires anywhere in the wheel wells and you're okay with it sitting at slightly lower than stock height i'd order up these: 1967-1976 Dodge A-Body Geometry Corrected Leaf Springs

the main reason is that i know they'll be decent quality, they come with the bushings and new hardware, and they're listed at 130 in/lb rate which is about what you want for street handling and to compliment the front t-bars. they also have a half leaf front so the forward section will be stiffer and you may not need a swaybar.

but as mentioned above, you could call espo and talk to them and see what they have to offer and that would give you another option.

Being that I want to go with 245s. I would like a little higher then stock height.I dont think the 245s will sneek all the way in the wheel well with those hotchkis leafs. It says that it lowers the car 1in.

I would be ok with the wheel well sitting right above the rim.

 

[64whiteghost]

Problem is. I already bought the mopar performance springs. :/ but i will call espo. And see what they say

Do you know how much height these SS mopar leafs give?

 

[junkyardhero]

Being that I want to go with 245s. I would like a little higher then stock height.I dont think the 245s will sneek all the way in the wheel well with those hotchkis leafs. It says that it lowers the car 1in.

I would be ok with the wheel well sitting right above the rim.

that was just kind of shoot from the hip, click the "buy" button suggestion.

contact espo. tell them what you're doing and tell them that if possible, you want a spring that is in the 120~140 lb/in

i would maybe go +1 or +2 and then use an adjustable front hanger to get it where i want it. if you still have the stock springs and they're not totally clapped out, i'd put everything together and see where you're at and from there you could determine what would work best.

 

[64whiteghost]

that was just kind of shoot from the hip, click the "buy" button suggestion.

contact espo. tell them what you're doing and tell them that if possible, you want a spring that is in the 120~140 lb/in

i would maybe go +1 or +2 and then use an adjustable front hanger to get it where i want it. if you still have the stock springs and they're not totally clapped out, i'd put everything together and see where you're at and from there you could determine what would work best.

Not a shoot from the hip

Ive had a 64 before and the height was low in the back. From what ive seen i need the back to up 1 inch and i will also higher the front one inch. Will give the car a better ride. In my opnion. My friend that is porting my heads has the SS springs and recommends them.

 

[junkyardhero]

i honestly can't say on SS springs. some say 1.5" some say 3"

anyway, i think that the waters muddied here going off on a tangent about spring rates and bars and balancing a system.

here's my take: the SS springs will work but they might not be optimal in ride quality, or handle to your expectations, they will more than likely be high enough in ride height to clear the tires. i would strongly discourage running a rear sway bar with them.

in the guise of use what you have, yeah, they'll do the job. i mean, nobody wants to drop coin on another set of something when you have it sitting there on the garage floor. you can put them in, see what shakes out. maybe they're exactly what you were looking for, maybe you hate them with the fury of 10,000 suns; but at least then you can make a more informed decision of what you actually want and the direction to take in order to get that.

 

[64whiteghost]

i honestly can't say on SS springs. some say 1.5" some say 3"

anyway, i think that the waters muddied here going off on a tangent about spring rates and bars and balancing a system.

here's my take: the SS springs will work but they might not be optimal in ride quality, or handle to your expectations, they will more than likely be high enough in ride height to clear the tires. i would strongly discourage running a rear sway bar with them.

in the guise of use what you have, yeah, they'll do the job. i mean, nobody wants to drop coin on another set of something when you have it sitting there on the garage floor. you can put them in, see what shakes out. maybe they're exactly what you were looking for, maybe you hate them with the fury of 10,000 suns; but at least then you can make a more informed decision of what you actually want and the direction to take in order to

Yes I agree. I appreciate your time and knowledge truly do. Thank you !

Im going to see about returning them and going to call hotchkiss and the other brand you sent me.

Thank you again !

 

[clifftt]

My last two cents … when I bought my ‘66 Formula S, it had rear end sag. My assumption was the springs were worn and aged letting gravity taking its effect for 50+ years.

I ordered my Espo springs as stock, not the +1 or +2. The replacement changed my car, giving it a slightly raked look. (They were replaced about four years ago, have not “settled” lower.) It gets compliments. Expect replacements of any kind to do this to yours, unless you go with a de-arched (lowering) spring.

 

[65 Cuda 340]

I just replaced the original 4-leaf rear springs in my 63 Valiant convertible with stock 340 springs. These were used springs I got at a swap meet a long time ago and finally got around to rebuilding, By rebuilding, I mean taking them apart, sand blasting them, assembling them with new zinc interleaves, plastic spacers and clamps, then painting with semi-gloss black urethane. Left the front spring bushings alone, new shackles. Did not re-arch any of the leaves. I was expecting the same ride height, but the 340 springs raised the back end up almost two inches. (I trimmed the clamp bolts before mounting the springs.)

 

[64whiteghost]

I just replaced the original 4-leaf rear springs in my 63 Valiant convertible with stock 340 springs. These were used springs I got at a swap meet a long time ago and finally got around to rebuilding, By rebuilding, I mean taking them apart, sand blasting them, assembling them with new zinc interleaves, plastic spacers and clamps, then painting with semi-gloss black urethane. Left the front spring bushings alone, new shackles. Did not re-arch any of the leaves. I was expecting the same ride height, but the 340 springs raised the back end up almost two inches. (I trimmed the clamp bolts before mounting the springs.)

View attachment 1716101254

Wow thats alot. I wouldnt like my car to be 2 inches higher.

Im leaning towards the Hotchkis set

 

[64whiteghost]

My last two cents … when I bought my ‘66 Formula S, it had rear end sag. My assumption was the springs were worn and aged letting gravity taking its effect for 50+ years.

I ordered my Espo springs as stock, not the +1 or +2. The replacement changed my car, giving it a slightly raked look. (They were replaced about four years ago, have not “settled” lower.) It gets compliments. Expect replacements of any kind to do this to yours, unless you go with a de-arched (lowering) spring.

Thank you for your response. Do you have pictures of your car ? I would like to see how much rake it gave them.

 

[clifftt]

Best pics I can offer you now. If I get the car out for a ride, I’ll shoot you better ones. Car has Firm Feel .940” bars in front and 215/65R15’s all around besides the rear Espo’s, stock Formula S bar in front, no rear bar, new 20:1 PST manual steering box. Corners nice enough for me in town at street-smart speeds.

 

[64whiteghost]

how do you want the car to sit? low? super low? stock-ish? a little rake with the *** up? how much wheel/tire do you want to show?

have you test fit the rims and tires? do you *need* it to sit at a specific height so that the tires don't rub anywhere?

i know this all seems very particular and overwrought, but all of this has a bearing on choosing springs that will work.

as a somewhat educated guess, if you're not fouling the tires anywhere in the wheel wells and you're okay with it sitting at slightly lower than stock height i'd order up these: 1967-1976 Dodge A-Body Geometry Corrected Leaf Springs

the main reason is that i know they'll be decent quality, they come with the bushings and new hardware, and they're listed at 130 in/lb rate which is about what you want for street handling and to compliment the front t-bars. they also have a half leaf front so the forward section will be stiffer and you may not need a swaybar.

but as mentioned above, you could call espo and talk to them and see what they have to offer and that would give you another option.

Question, The Hotchkiss Leaf springs says 1967. Will they fit my 1964 ? or did the leaf spring design change in 67?

 

[RustyRatRod]

a large rear swaybar can tend toward oversteer. even more so in a system that's not thoroughly balanced.

a 7/8" bar is absolutely massive, especially if it's solid. i'd go smaller, much smaller. depending on the design of your rear springs you may not even need a rear bar.

I was lookin in my pants this mornin and that's the word I used. "Massive". You know what's too bad? That I didn't make it to the toilet in time.