What's a good starter suspension system that can be upgraded later?

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Dragin Demon

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Hello everyone,

I'm currently restoring a '72 Demon which is mostly just a shell body on a rotisserie.

My intentions for it is to make it a slightly resto-mod street rod. I'm currently trying to get it on the road as quick as I can.

I'd like to use a Hotchkis TVS suspension system, which is around $2,000. However, if I can put in a suspension system that's cheaper than that for now, I can get the car on the road quicker and then later on make upgrades.

So my question is, what would be a good baseline mixture of stock and upgraded suspension parts to start out with? I was thinking about buying upgraded leaf springs, shocks, and sway bars and leaving the rest stock.

I am adding subframe connectors and a radiator brace while the car's on the rotisserie so those should help as well.

Thanks!
 
Start with the K-member. Get it hot tanked and blasted. Then go to Firm Feels website and look at what they do to them to reinforce them and duplicate that. Get some lower control arm plates or make some. After that you can pieces as you go. Buy some 1" or bigger T-bars for sure.
 
I'm using the QA! setup. It can be bought and installed in pieces and costs hundreds for each compenent totaling under 1500$
 
For a street car stick with the stock K member like swinger said. If its off the car now, do a reinforcement on it by seam welding everything and gusseting the steering box mount.

Install a bigger set of torsion bars. 1" at least, up to about 1.06" unless you're planning on tracking it. The torsion bars alone will make a HUGE difference, especially with subframe connectors already in.

Sway bars are a great addition. You don't have to get the biggest ones out there, especially if you've gone with bigger torsion bars. An adjustable rear bar is a good idea, as these cars don't usually need as much rear bar as they do front. The rear springs are pretty close to the right spring rate, so unless they're totally worn out you can actually use the stock rear springs for a while. Of course, if they're sagging like most are they should be replaced.

Shocks are the next big item, a good set of shocks like the RCD Bilstiens or Hotchkis Fox's are a huge addition. Depending on what brakes you already have, you may be able to leave those alone for awhile. The stock disks work fine for the street, and you can upgrade to 11.75" disks with just a set of caliper brackets if you already have 73+ spindles. Those work pretty darn well, you can hold off on the super expensive big brake kits if you go that route. I run 11.75" mopar rotors and the stock calipers on my Challenger with 11" rear drums, and it stops very well for a big old E-body.

Tires are a HUGE improvement as well, go 17's or 18's with a modern compound tire. Set up correctly, a Demon can run 275/40/17's all the way around. Or 255's if you don't want to get that crazy. That by itself will do amazing things for your traction, which is why the bigger torsion bars are so important. There are pretty much NO performance street tires in 15" anymore, BFG T/A's and their clones are barely a step above hockey puck rubber.

Of course I just laid out a few thousand dollars worth of parts, but I'll add some good news. You don't need tubular ANYTHING. Not UCA's, not LCA's, not the K member, none of it for a street car. I'd also stay away from heim joints on the street. Get a set of offset Moog UCA bushings and a set of stock BBP UCA's and you'll be fine. If you really want to, tubular UCA's would be my exception to the tubular rule because of the built in adjustment for better caster, but make sure they're the bushed kind for the street. You'll be much happier. I've run tubular UCA's and LCA's for around 40k miles, and still have a set of Hotchkis UCA's with heims and the difference vs. rebuilt stock parts with poly bushings is almost non-existent on the street. For a track car it will make a difference, but for a street car its mostly just a headache. The adjustable heim UCA's take some setup to get right, so unless you're doing your own alignments there's a few trips to the alignment shop. And the heims wear quicker than poly or even rubber bushings on the street. And they're expensive, and that money is better spent elsewhere.
 
72bluNblu said:
For a street car stick with the stock K member like swinger said. If its off the car now, do a reinforcement on it by seam welding everything and gusseting the steering box mount.

Install a bigger set of torsion bars. 1" at least, up to about 1.06" unless you're planning on tracking it. The torsion bars alone will make a HUGE difference, especially with subframe connectors already in.

Sway bars are a great addition. You don't have to get the biggest ones out there, especially if you've gone with bigger torsion bars. An adjustable rear bar is a good idea, as these cars don't usually need as much rear bar as they do front. The rear springs are pretty close to the right spring rate, so unless they're totally worn out you can actually use the stock rear springs for a while. Of course, if they're sagging like most are they should be replaced.

Shocks are the next big item, a good set of shocks like the RCD Bilstiens or Hotchkis Fox's are a huge addition. Depending on what brakes you already have, you may be able to leave those alone for awhile. The stock disks work fine for the street, and you can upgrade to 11.75" disks with just a set of caliper brackets if you already have 73+ spindles. Those work pretty darn well, you can hold off on the super expensive big brake kits if you go that route. I run 11.75" mopar rotors and the stock calipers on my Challenger with 11" rear drums, and it stops very well for a big old E-body.

Tires are a HUGE improvement as well, go 17's or 18's with a modern compound tire. Set up correctly, a Demon can run 275/40/17's all the way around. Or 255's if you don't want to get that crazy. That by itself will do amazing things for your traction, which is why the bigger torsion bars are so important. There are pretty much NO performance street tires in 15" anymore, BFG T/A's and their clones are barely a step above hockey puck rubber.

Of course I just laid out a few thousand dollars worth of parts, but I'll add some good news. You don't need tubular ANYTHING. Not UCA's, not LCA's, not the K member, none of it for a street car. I'd also stay away from heim joints on the street. Get a set of offset Moog UCA bushings and a set of stock BBP UCA's and you'll be fine. If you really want to, tubular UCA's would be my exception to the tubular rule because of the built in adjustment for better caster, but make sure they're the bushed kind for the street. You'll be much happier. I've run tubular UCA's and LCA's for around 40k miles, and still have a set of Hotchkis UCA's with heims and the difference vs. rebuilt stock parts with poly bushings is almost non-existent on the street. For a track car it will make a difference, but for a street car its mostly just a headache. The adjustable heim UCA's take some setup to get right, so unless you're doing your own alignments there's a few trips to the alignment shop. And the heims wear quicker than poly or even rubber bushings on the street. And they're expensive, and that money is better spent elsewhere.
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Agree 100% on all this
 
72BBSwinger said:
Start with the K-member. Get it hot tanked and blasted. Then go to Firm Feels website and look at what they do to them to reinforce them and duplicate that. Get some lower control arm plates or make some. After that you can pieces as you go. Buy some 1" or bigger T-bars for sure.
Click to expand...

72bluNblu said:
For a street car stick with the stock K member like swinger said. If its off the car now, do a reinforcement on it by seam welding everything and gusseting the steering box mount.

Install a bigger set of torsion bars. 1" at least, up to about 1.06" unless you're planning on tracking it. The torsion bars alone will make a HUGE difference, especially with subframe connectors already in.

Sway bars are a great addition. You don't have to get the biggest ones out there, especially if you've gone with bigger torsion bars. An adjustable rear bar is a good idea, as these cars don't usually need as much rear bar as they do front. The rear springs are pretty close to the right spring rate, so unless they're totally worn out you can actually use the stock rear springs for a while. Of course, if they're sagging like most are they should be replaced.

Shocks are the next big item, a good set of shocks like the RCD Bilstiens or Hotchkis Fox's are a huge addition. Depending on what brakes you already have, you may be able to leave those alone for awhile. The stock disks work fine for the street, and you can upgrade to 11.75" disks with just a set of caliper brackets if you already have 73+ spindles. Those work pretty darn well, you can hold off on the super expensive big brake kits if you go that route. I run 11.75" mopar rotors and the stock calipers on my Challenger with 11" rear drums, and it stops very well for a big old E-body.

Tires are a HUGE improvement as well, go 17's or 18's with a modern compound tire. Set up correctly, a Demon can run 275/40/17's all the way around. Or 255's if you don't want to get that crazy. That by itself will do amazing things for your traction, which is why the bigger torsion bars are so important. There are pretty much NO performance street tires in 15" anymore, BFG T/A's and their clones are barely a step above hockey puck rubber.

Of course I just laid out a few thousand dollars worth of parts, but I'll add some good news. You don't need tubular ANYTHING. Not UCA's, not LCA's, not the K member, none of it for a street car. I'd also stay away from heim joints on the street. Get a set of offset Moog UCA bushings and a set of stock BBP UCA's and you'll be fine. If you really want to, tubular UCA's would be my exception to the tubular rule because of the built in adjustment for better caster, but make sure they're the bushed kind for the street. You'll be much happier. I've run tubular UCA's and LCA's for around 40k miles, and still have a set of Hotchkis UCA's with heims and the difference vs. rebuilt stock parts with poly bushings is almost non-existent on the street. For a track car it will make a difference, but for a street car its mostly just a headache. The adjustable heim UCA's take some setup to get right, so unless you're doing your own alignments there's a few trips to the alignment shop. And the heims wear quicker than poly or even rubber bushings on the street. And they're expensive, and that money is better spent elsewhere.
Click to expand...

Listen to these two fellows.......they have a VERY GOOD understanding what it takes to make one of these clunkers handle with factory style stuff....
 
Might also want to watch
[ame="http://www.youtube.com/watch?v=Nwes-SP8u4w"]Control arm repair - YouTube[/ame]
it is from Jim Lusk, a member here.
 
only thing to add after welding the k member is go full poly bushing kit. the t bars can be swapped easily, the shocks can swap, sway bars can be added.

full front rebuild kit with idler and pit
reinforce k and control arms.

and other posts, anyone make a bushed adjustable strut rod yet? I would love to see a poly bushed strut rod to let the control arm move thru its motion easier...
 
805moparkid said:
only thing to add after welding the k member is go full poly bushing kit. the t bars can be swapped easily, the shocks can swap, sway bars can be added.

full front rebuild kit with idler and pit
reinforce k and control arms.

and other posts, anyone make a bushed adjustable strut rod yet? I would love to see a poly bushed strut rod to let the control arm move thru its motion easier...
Click to expand...
DO NOT use poly lower control arm bushings... they WILL pound out of shape in short order. poly is good everywhere else but factory rubber in the lowers is best thing to use. And yes, I also know one or two things about making a mopar handle.....
 
You can do a coilover conversion on a factory K member. Check out MagnumForce to see what they have available.
 
The one issue with the factory uppers is the lack of adjustment. RMS makes a nice set.
 
-Hotchkis or Hellwig front sway bar and rear adjustable sway bar.
-About .97 to 1.03" torsion bars
-moog offset pn. 7103 upper control arm bushings installed for more caster
-rubber LCA bushings
-poly strut bushing with rear bushing cut 3/16" off and steel tube the same amount.
-Bilstein RCD shocks

Reinforcing the K-member would be great if it's out of the car and it fits your budget. It's a core piece that's a lot of work to do later. But it's not as "bang for your buck" and "feel it in the seat of your pants" as the items above.

Use your current rear leaf springs if they are V-8 units. They are probably sagging enough where you will not need lowering blocks and front lowering perch. Hotchkis special handling leafs are great if there is room in your budget for them. But they will lower the rear a lot. OK if you want the front is lowered a lot to match.
 

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Hey Dragin Demon -
The only thing that bothers me is the title of this thread. Why? Because it sounds like you want to spend some money now, but not too much. And then you want to spend more money later to reach your ultimate goal.
So, one observation and one question:
  • During your buildup you run the huge risk of running with some major suspension items that aren't designed to work together. This can be dangerous and you certainly will not be happy with a cobbled together system
  • How much more is it going to cost to buy parts separately over a period of time rather than saving and buying a packaged kit that's proven to work?
As always, your money and your decision.
But I learned the hard way about double-spending during a build project.
Best of luck on whichever way you decide to go.
 
Not sure I agree. My own is sort of a "work in progress." Where we are at right now was recently original front drums, just got through finally getting disk brakes under there. In between, went from fairly worn old shocks, to new but "so so" shocks, and from original T bars to some big ones out of a parts car, .9" or so. At the moment, I still don't have the sway bar hooked up. It's "next on the list."

From the start, somewhere in the middle, and to the "now," it wasn't dangerous to drive at all. Went right down the highway at 70 and with modern tires, certainly handled better than when it was new with 2.50 X 12" LOL original tires.
 
Dragin Demon said:
I am adding subframe connectors and a radiator brace while the car's on the rotisserie so those should help as well.

Thanks!
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Someone correct me if I'm wrong, but I believe you want to install the subframe connectors with weight on the wheels; engine and tranny installed etc.
 
adamm said:
Someone correct me if I'm wrong, but I believe you want to install the subframe connectors with weight on the wheels; engine and tranny installed etc.
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You're not wrong, but I've heard a TON of different and conflicting ideas on this one. Some say that the car should be leveled on jackstands, others install them with the car upside down on a rotisserie, or even sideways on a rotisserie.

If you're installing them with the car fully assembled, it makes sense to do it the way you described so you don't have to redo all the body fits. If the car is apart, you have to hang and fit all the panels anyway. I've seen folks install frame connectors every way I've mentioned above, and haven't heard of any of them having issues. I think the only wrong way to do it would be to chain the frame to ground and apply some kind of hydraulic force. And even then, I can think of certain instances where that might actually be beneficial...

As far as the mismatched parts go, it really depends on the parts. Upgrading springs and torsion bars without adding sway bars isn't a big deal, the car will handle better than stock. Same with adding bigger torsion bars and springs and leaving the stock hockey puck tires on there. The car will still handle better. Now, I wouldn't install giant new torsion bars without rebuilding the front end, replacing all the bushings and tie rod ends etc. The new springs and torsion bars with old shocks might make things a little interesting, but I'd bet it would still handle better than stock. Might ride a little weird though .

I would definitely upgrade the brakes before I upgraded the rims and tires. 9" drums barely work as it is, they don't need the extra rotational weight of say, a set of 275/40/17's on the front. And you don't want to find out that the new rims and tires you just bought for the car a month ago won't fit because your new disks changed the track width of the front end (and they do).
 
My car came with an awesome suspension set underneath. It's "stock" brand. Some poly bushings, a sway bar, some T-bars, and a reinforced K frame later, it's now the "rocks" brand.

Where are people buying the Aussie Poly offset upper bushings? I can make a set if need be, but sometimes it's easier just to buy 'em.
 
jos51700 said:
My car came with an awesome suspension set underneath. It's "stock" brand. Some poly bushings, a sway bar, some T-bars, and a reinforced K frame later, it's now the "rocks" brand.

Where are people buying the Aussie Poly offset upper bushings? I can make a set if need be, but sometimes it's easier just to buy 'em.
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poly offsets? here in AZ our rubber bushing last about a year due to the extreme heat in the summer which is the reason i wont run rubber stuff.

where do you get these poly offset bushings?

also i hear there is a LCA pin that has been changed for poly lowers, is that true? if not what is a way to make the lower poly's live?
 
This is an awesome thread with lots of great info and with the posters being guys that have tried all kinds of different set ups too.

Thanks to all you guys:thumblef:
 
805moparkid said:
poly offsets? here in AZ our rubber bushing last about a year due to the extreme heat in the summer which is the reason i wont run rubber stuff.

where do you get these poly offset bushings?

also i hear there is a LCA pin that has been changed for poly lowers, is that true? if not what is a way to make the lower poly's live?
Click to expand...

There's a company called Pedders in Australia that sells offset polys. Especially factoring in shipping to U.S.A. They are very expensive for what they are. Might as well buy tubular A-arm with pre installed polys and UBJ's for that price.

Plus there's more geometry binding when running poly offsets. Each bushing is a plain bearing that rotates on only on one axis. With mopar upper control arms, the front and rear bushings are adjusted individually. Different than a GM or Mustang with a straight dogbone that is shimmed for adjustment.

Therefore you can't put an imaginary straight rod through the front and rear upper control arm bushings in a Mopar after you adjust them. The front and rear bushings will be on a slightly different axis. With offset bushing there is an even greater difference of axis.

With rubber bushings are more compliant to make up for the difference of axis.

Just run the Moog rubber offsets.

If all rubber bushings only last ONE year in AZ the dealers would be swamped with warranty work. I figure that is an exaggeration. Rubber products might not last as long in AZ. But they don't spontaneously combust.
 
autoxcuda said:
There's a company called Pedders in Australia that sells offset polys. Especially factoring in shipping to U.S.A. They are very expensive for what they are. Might as well buy tubular A-arm with pre installed polys and UBJ's for that price.

Plus there's more geometry binding when running poly offsets. Each bushing is a plain bearing that rotates on only on one axis. With mopar upper control arms, the front and rear bushings are adjusted individually. Different than a GM or Mustang with a straight dogbone that is shimmed for adjustment.

Therefore you can't put an imaginary straight rod through the front and rear upper control arm bushings in a Mopar after you adjust them. The front and rear bushings will be on a slightly different axis. With offset bushing there is an even greater difference of axis.

With rubber bushings are more compliant to make up for the difference of axis.

Just run the Moog rubber offsets.

If all rubber bushings only last ONE year in AZ the dealers would be swamped with warranty work. I figure that is an exaggeration. Rubber products might not last as long in AZ. But they don't spontaneously combust.
Click to expand...

well i know at work we have a hell of a time with the rubber bushings and seal lips dry rotting... i just dont want to have to mess with it and tubular sounds the way to go, firm feel's were the best fitting with deep 16's if i recall right?
 
This is exactly the kind of information I was looking for. Thank you.

I actually don't have a K member for the car yet, so I'm looking into the best option there for me as well.
 
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