s6 to V-8 do I need to change torsion bars

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Danco

Danco

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I am currently working on a 74 duster and planning to swap s6 for 360 C.I. I thought I read somewhere that I had to replace or upgrade my torsion bars for larger diameter ones. I am not sure what to do.
any suggestions? are there any aftermarket sources for these?

thanks
 
For anything else other than drag racing, I would deffinately upgrade the bars. "Firm Feel inc." is one good source as is "just suspension"
 
If you don't want to baby it over every driveway transition and bump in the road, yes.
Oversize those bars and you will be very glad you did, I promise.
 
thanks for your suggestions, greatly appreciated. now all I have to do is find some
 
Front sway bar also a nice addition for handling with good shocks.
 
I say NO!

From the been there and done that camp.
 
Drag racers look for the thinner slant bars, to give better weight transfer to the rears, but otherwise thicker is better. Measure what you have first. There are charts to help tell what you have, based on the PN on the end or the colored paint marks, or just use a vernier caliper. Slants w/ factory AC had the same PN as 2-bbl V-8 (w/o AC?), at least in some years. However, even most V-8 bars are too springy for people today.
 
I ran slant 6 bars on a couple small block A bodies for years when I was younger. If you're pressed for cash, I'd put the money into other parts. You don't "have" to replace them.

How about you give us more info on your situation and whatnot?
 
You don't have to upgrade them, your car won't burst into flames or anything if you don't.

On the flip side, I'm with Jim. I had /6 bars in my '74 Duster, and they were horrific even with the /6 in it.

These cars were undersprung from the factory. Even cars with the factory bars that are correct for the engine they're equipped with don't handle well, bottom out the suspension, etc. And keep in mind the original bars are 40+ years old. If you're at all used to the handling and ride quality of more modern cars, you should put larger bars on the car. Larger than even the factory V8 bars.

Firm Feel, PST, and Just Suspension all make torsion bars for A-body's like your Duster. My recommendation would be to get a set of bars close to 1" in diameter if you're building a car for the street. The 1" to 1.03" bars offered by those manufacturers are pretty good for the street, they'll significantly improve the handling abilities of your car without rattling your eyeballs out of your head if they're matched to a decent set of shocks.
 
thanks guys I plan on getting the PST torsion bars at a later date. this is my first "full" restore. this one will be a rotisserie. planning on a 360 C.I. 4 spd 8.75 rear. currently in the stripping stage. money is somewhat of a concern but probably a 5 year target for completion.

I find you guys plenty helpful in all the forums. glad I signed up
again thanks
 
Danco said:
thanks guys I plan on getting the PST torsion bars at a later date. this is my first "full" restore. this one will be a rotisserie. planning on a 360 C.I. 4 spd 8.75 rear. currently in the stripping stage. money is somewhat of a concern but probably a 5 year target for completion.

I find you guys plenty helpful in all the forums. glad I signed up
again thanks
Click to expand...

PST gives us a discount, but call them when you are ready.
That way you can make sure you are getting the member discount.

I run a 318 and got the factory indexed 1.03 bars and couldn't be happier about them.
The car was always hitting the bump stops in dips and even an occaisional bottom out on the K, (and I run 15 tires) so...

Rumblefish must live in an area with all new streets or something. :D
 
Im getting ready to drop a 1963 big block in my 70 swinger what size torsion bars do you all recommend originally its a /6
 
I beat the crap out of my v8 duster with slant 6 bars . never had an issue. Pot holes, speed bumps, driveway transitions, you name it , been there done that.
 
73AbodEE said:
I beat the crap out of my v8 duster with slant 6 bars . never had an issue. Pot holes, speed bumps, driveway transitions, you name it , been there done that.
Click to expand...

I wonder what the determining factor there was then?
The bars that were in my car when I got it were 890's and they were pretty mushy.
Felt like driving a boat in lake.

Hmm
 
73AbodEE said:
I beat the crap out of my v8 duster with slant 6 bars . never had an issue. Pot holes, speed bumps, driveway transitions, you name it , been there done that.
Click to expand...

oops, doubled up. :)

Felt like driving a boat in lake, even with them turned up where the ride height was to high.
 
TrailBeast said:
I wonder what the determining factor there was then?
The bars that were in my car when I got it were 890's and they were pretty mushy.
Felt like driving a boat in lake.

Hmm
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Ride height will change the amount of time you spend on the bumpstops. The rest comes down to what you're used to/willing to put up with as a driver.

All A-bodies with /6 bars will feel like you're driving the Queen Mary. That's just what a 100 lb/in spring rate bar on the front of a 3,000-3,500 lb car feels like. If you're ok with that :dontknow:. I mean, I don't even like how they ride with the stock V8 bars, they're only 120 lb/in. Although it might not sound like much, that still amounts to a 20% increase in rate over the /6 bars.

But I also thought the Just Suspension 1" bars were too soft too, and they're close to a 200% increase in rate. Some of that is just driver preference, some of it is how the car actually gets used, both of which are pretty subjective. And the rest of the car's set up matters too- shocks, sway bars, and the choice/size of the tires make a huge difference.
 
I have dropped in V8's more than a few times into slant 6 car and never changed the bars.I never really noticed a differance in handling.
 
68383GTS said:
TrailBeast said:
I wonder what the determining factor there was then?
The bars that were in my car when I got it were 890's and they were pretty mushy.
Felt like driving a boat in lake.

Hmm
Click to expand...
I have dropped in V8's more than a few times into slant 6 car and never changed the bars.I never really noticed a differance in handling.
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me either , ever. the front end of my last duster did not float , and was rather harsh. it was stiff as a board. the slant six is still a cast iron engine and is not that much lighter than a V8. people act as if its made of aluminum. hell the bars in my charger are .96 and running around with a 440 on them , the front of that is pretty stiff as well. I load them up pretty good too. when you lower the front end it is going to make it softer , and if you have old shocks , that just makes it worse.
 
73AbodEE said:
me either , ever. the front end of my last duster did not float , and was rather harsh. it was stiff as a board. the slant six is still a cast iron engine and is not that much lighter than a V8. people act as if its made of aluminum. hell the bars in my charger are .96 and running around with a 440 on them , the front of that is pretty stiff as well. I load them up pretty good too. when you lower the front end it is going to make it softer , and if you have old shocks , that just makes it worse.
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Changing the ride height does not change the spring rate. It doesn't even change the pre-load significantly. The car still weighs the same, and the torsion bar adjuster only changes the angle of the LCA with respect to the torsion bar socket. "Pre-load" on a torsion bar car is set almost entirely by the weight of the car. There is a small variation of the effective wheel rate from changing the angle of the LCA because that changes the "effective" length of the lever acting on the torsion bar, but that effect is pretty small. And only relevant at that particular angle, since the effective wheel rate is always changing as the suspension moves through its arc.

As far as any car with /6 bars being "harsh" it's because it was probably on the bump stops. Otherwise, I can only say that your definition of "did not float" and " rather harsh" are completely different from how I define them. Because every car I've ever driven with /6 bars was the very definition of "floaty". The only time I've ever experienced a slant 6 torsion bar equipped car that didn't feel floaty and horribly vague is when that car was actually sitting on the bump stops. In which case they DO ride harsh, because there's no suspension travel at all.
 
What he said
Well, if your ride height is set to where the /6 bars let the car settle onto the bumpstops on every corner, yeah it handles. And when the wheel drops into a hole, big deal. And when you hit a speed bump again all that shock goes into the bumpstops.So what if it rattles the fillings outta yer teeth.And eats bumpstops.The only way around it is stiffer shocks.And then the ride goes to pot.
I was done with /6 bars on the street,decades ago.If anyone wants to try and follow me around and keep up,with your /6 barred V8 road burner, you better have a lot more motor than me.Heehee
IMO the 1.03s are barely adequate, under my 366 S-clone. The only reason I havent upgraded them is Im nearly 62, and should be slowing down soon. So they tell me.
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Danco; Like was said, your car wont catch fire if you dont swap them out. Drive the car for a good long while. Perhaps they will suit your driving style and environment just fine.The bars are just one part of the system,that includes the shocks,the swaybar,the bumpstops,the bushings, the alignment settings,the powertrain, and even the brakes.Its a system. Your current system was designed by some very competent engineers.
Let the fillings in your teeth be the decision makers.
 
not even close to riding on the bumpstops. the front bumper would be dragging the ground if that were the case. if it was , I would have fixed that immediately. the only thing I did to this car was yank the 6 , and drop a 318 in it. I ran the entire six suspension for over 2 years , 7 1/4 , and all . this was my daily driver. the front end had a 3" window of ride height using the torsion bar adjusters. and yes , it was stiff when the bars were loaded up. I lived out in the boonies and this car saw plenty of dirt , ditches, washboards and everything in between, every day. the long tube headers never even scraped the ground, not one time. all I am doing is sharing my personal experience using a V8 with a slant suspension.
 

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IMO the "float" problem that some are reporting can be ameliorated by a good set of HD gas shocks. Raising the spring rate at one end of the car upsets the balance that Ma Mopar put into it. So does upping the engine weight. That can be countered by an aluminum intake on the 360 and moving the battery to the trunk.

Usually, increasing the engine weight promotes more understeer. Conversely, increasing the front spring rate should promote more oversteer. What happens when you put in a 360 and 1" TBs?? Who knows??

I can't speak for the 74 model, but the 73 /6 uses the same bar as the 318 w/o A/C. (source: 73 Dodge Parts Manual) That tends to validate the assertion that the weight difference between the 318 and 225 is not that much.
 
73AbodEE said:
not even close to riding on the bumpstops. the front bumper would be dragging the ground if that were the case. if it was , I would have fixed that immediately. the only thing I did to this car was yank the 6 , and drop a 318 in it. I ran the entire six suspension for over 2 years , 7 1/4 , and all . this was my daily driver. the front end had a 3" window of ride height using the torsion bar adjusters. and yes , it was stiff when the bars were loaded up. I lived out in the boonies and this car saw plenty of dirt , ditches, washboards and everything in between, every day. the long tube headers never even scraped the ground, not one time. all I am doing is sharing my personal experience using a V8 with a slant suspension.
Click to expand...

based on the picture of your jacked up duster, I am going to figure you have no real concept of a "good" handling car......and just leave it at that.
 
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