What is the Best Suspension Setup for 3rd Gen

[moparfreak]

Hello folks,

Well it's been quite some time for me. I fell in love early on w/ Mopars, and I've had a '73 Charger SE for 15 years now, since my sophomore year of college (not saying it was the wisest purchase of my life, but I'm attached to it now). Fastforward, and I've moved into a home, built a proper shop, and I've now got the space and tools to start a proper restoration of this car.



As I start planning out the main points of the job, one thing that I'd like to do is improve the drive-ability of this car. It's a freakin' boat, the steering's unresponsive and the factory suspension is obviously not set up well for a car of this size. So, it brings me to the question:

What is the optimum setup for this car? I am assuming rack & pinion steering? Is sticking w/ torsion bar or are there front independent styles that have worked well? I know there's probably tons of stuff out there for converting 2nd Gens to whatever you could dream up but 3rd Gens are much more limited.

Any advice here in figuring out what's out there and works well would be great. I want to turn this into a fun car to cruise and daily drive in the summer months here in WI as the seasons allow. Don't care about factory specs or concours restoration or any of that stuff...

Thanks,
Adam

[72Charger72]

 

[HPP]

Call the guys up at Firm Feel and talk to them. They offer the most complete packages of stock based equipment to step up the handling of your generation of Charger.

A few things they will probably recommend:
replacing all the rubber, isolated ride bushings in the K frame and rear suspension with urethane
stepping up t-bar size
stepping up sway bar size
stepping up  rear spring rate
stepping up shock quality
going with a stage 2 or 3 steering box
a much more aggressive alignment spec
4 wheel thrust alignment to those specs

There are no decent rack and pinion conversions out there without replacing the entire front suspension for around $8000

[440]

Drive it like in an 80's movie 

[moparfreak]

Call the guys up at Firm Feel and talk to them. They offer the most complete packages of stock based equipment to step up the handling of your generation of Charger.

A few things they will probably recommend:
replacing all the rubber, isolated ride bushings in the K frame and rear suspension with urethane
stepping up t-bar size
stepping up sway bar size
stepping up  rear spring rate
stepping up shock quality
going with a stage 2 or 3 steering box
a much more aggressive alignment spec
4 wheel thrust alignment to those specs

There are no decent rack and pinion conversions out there without replacing the entire front suspension for around $8000

Thank you, this is helpful they seem to have a wealth of parts and knowledge, and are also well regarded here it seems. I will definitely be giving them a call to spec out what would be appropriate for my build.

In researching different steering options this R&P setup came up, through Speedway, made by Unisteer. Does anyone have experience with this type of kit? Not that $1k isn't a lot, but a full refurb of steering box and arms through Firm Feel would cost similar...

https://www.speedwaymotors.com/1968-74-Mopar-B-Body-Rack-and-Pinion-Kit-B-B-Engine,38452.html
https://static.speedwaymotors.com/pdf/910-32319.pdf

Thanks,
Adam

[HPP]

Problem with most bolt on R&P systems, Unisteer in particular, is that they have reduced turning radius and increased bump steer problems.  So you spend a grand for slightly better feel with a couple of major drawbacks. For a stock box, stepping down the pressure in the stock mopar pump can help eliminate the mopar over-assist and improve feel, as can going to the stage 1,2, or 3 box, while adding faster ratio pitman and idler arms can speed up response.

Another option is to use the modern Borgeson/Delphi conversion box. While still a recirculating worm gear system, these are built off new core boxes with much tighter tolerances, improved feel, and different ratios than stock. For new vehicles not utilizing an R&P system, the Borgeson box is what  is used in place of it.

IMO, a lot of the mush and sloppy response in the 1973 and newer years is worn out bushing in the front suspension, which has about twice as many in it as the 1972 model years and older.

[flyinlow]

I have done most of what HPP said to my '73. It drives well for a 45 year old car with a pick up truck suspension (tbar/leafs) .  Optimum ? for me in the $ 2000-3000 range  and staying somewhat original design it works well.

17-18 wheels  with modern tires help a lot. They do ride harsher with 40 series tires and I bent a wheel on a nasty chuck hole. Went back up to 45 series, improved the ride some with 1/2 inch more side wall.

[moparfreak]

Problem with most bolt on R&P systems, Unisteer in particular, is that they have reduced turning radius and increased bump steer problems.  So you spend a grand for slightly better feel with a couple of major drawbacks. For a stock box, stepping down the pressure in the stock mopar pump can help eliminate the mopar over-assist and improve feel, as can going to the stage 1,2, or 3 box, while adding faster ratio pitman and idler arms can speed up response.

Another option is to use the modern Borgeson/Delphi conversion box. While still a recirculating worm gear system, these are built off new core boxes with much tighter tolerances, improved feel, and different ratios than stock. For new vehicles not utilizing an R&P system, the Borgeson box is what  is used in place of it.

IMO, a lot of the mush and sloppy response in the 1973 and newer years is worn out bushing in the front suspension, which has about twice as many in it as the 1972 model years and older.

Thanks for the feedback. Didn't realize R&P reduces turning radius, definitely don't want to head that way....and a new custom tube k-member, well yeah that's not in the budget for a car like this...

It certainly seems there's a lot of folks that have had much success going to a FF type rebuilt steering box. Seems most of the discussion tends to be whether to go Stage II vs. Stage III, which I can deal with when the time comes.

Thanks,
Adam

[moparfreak]

I have done most of what HPP said to my '73. It drives well for a 45 year old car with a pick up truck suspension (tbar/leafs) .  Optimum ? for me in the $ 2000-3000 range  and staying somewhat original design it works well.

17-18 wheels  with modern tires help a lot. They do ride harsher with 40 series tires and I bent a wheel on a nasty chuck hole. Went back up to 45 series, improved the ride some with 1/2 inch more side wall.

flyinlow,
I'd be curious to know what your particular steering / suspension setup is, where you sourced parts, etc. It's hard finding actual '73 examples out there to see what's been successful. What did it take to go up in rim size? Any modifications needed for that? What type of brake setup do you have? Did you stick w/ stock control arms?

Thanks,
Adam

[RallyeMike]

What HPP said. You'd be surprised how much improvement can be made.

Nobody mentioned adding a rear sway bar yet.... Your SE done not have one at all originally.

[flyinlow]

I have

flyinlow,
I'd be curious to know what your particular steering / suspension setup is, where you sourced parts, etc. It's hard finding actual '73 examples out there to see what's been successful. What did it take to go up in rim size? Any modifications needed for that? What type of brake setup do you have? Did you stick w/ stock control arms?

Thanks,
Adam

Firmfeel 1.06 T-bars, Mopar HD leaf springs,  Larger front , added rear Antisway bars (ebay), poly sway bar bushings, Steer and Gear stage 2 steering box. Welded up seams on k-frame added a gussets near steering box , Bilstein shocks (firmfeel), all new Moog bushings and ball joints, added gussets to stock  lower control arms, home made frame ties, poly k-frame bushings (energy suspension?)

Aligned wheels for max positive caster (about 4deg. in my case) , 1/2 deg neg. camber ( increased front tire wear) and 1/16 toe in.  Lowered the front of the car slightly (looks better)  

18x8 fronts 245/45-18 Gmax5,  18x9.5 rear 275/40-18 gmax5 .  Removed 15" Cragars , BFG 245/275 and bolted on the 18" Riddlers.

Front brakes 11.75 Mopar ,sloted rotors , Hawk HPS pads, rear 11.5 sloted rotor Right stuff kit, Hawk HPS pads. Mopar aluminum master cylinder ( Dr. Diff),  Willwood proportioning valve. Thinking about larger front brake kit from Dr. Diff.  
The rear disk brakes require , Green bearing axle bearing for the 8 3/4 axle. Dr. Diff kits use the factory roller bearing which is a better choice in my opinion, but they where not out when I made the switch. Rear disks do not seam make the car stop any quicker , they just look cooler thru the wheels. Parking brakes suck on rear disk compared to drum brakes.