Suspension Info sources

[cuda2002]

I have a 73 'Cuda that I am building. The car came with a '69 383 which I have done some work on, it was originally a 318 car. The body work is near complete and I want to turn my attention to the suspension. The suspension as far as I am aware is stock and of course 30 years old.

Although I do want the car to be fast in a straight line, the fact is that I will be driving this car regularly and I want it to handle much better (even with the big block); more like a modern car . The car has power steering, front discs and front and rear sway bars.

I am looking for a good reference source so I can do some reading before I jump into making any major changes. I see in the recent Mopar Action magazine that the addition of torque boxes may be a consideration. Apparently, these torque boxes were used on cop cars, convertibles and hemi cars (no mention of the AAR and TA's). Sounds like this was done for both handling high torque engines as well as improve handling, stiffness.

I've been toying with the following ideas: going to 17" wheels with 235 R45's in the front and 265 R45's in the rear. New heavy duty rear springs, polygraphite front rebuild kit, maybe adding the torque boxes. Phase 2 might be tubular control arms,rear discs, bigger torsion bars and sway bars? depending on how hard my budget gets hit.

I want to know what will give me the biggest bang for my buck and what to avoid because of other potential problems it might cause. Any reference books or advise from anyone who has done this would be greatly appreciated.

Thanks in advance.

[LA360Dart]

cuda2002;

Layson's has a pair of books about Mopar's one of them was about handling. It's in their catalog www.laysons.com or call 877 930 4088 to order. hope this helps saw them at fall fling.

[cuda2002]

Thanks LA360Dart,

I will order that book. It looks like it will address alot of my questions.

I would still be interested in hearing from anyone who has done suspension mods, how they turned out and any advise they may have.

Cheers!!

[pro69bee]

I put frame conectors, big help , poly in rear leafs and strut rods, Magnum force upper arms ,big help too,Mopar sway bars front and rear,another big help. Boxed lower control arms and put rubber bushing in it.11/16 tie rods . Wheels are 15 by 10 rod lights with bfg 295 50s rear and 15 by 8 with 265 50s front.Also mopar .96 torsion bars. It all wokes real nice.Handles like a big Corvette,but still rides nice. KYB shocks work well with my combo, a 69 super bee with 383 4spd. I want to go to 16 or 17 wheels and hp tires but right offsets and styles are difficult to choose,and are usually verry heavy compared to 14 lb welds I now have.The weight of most 17s are around30 lbs.

[eckertt@epri.co]

I just today ordered the poly front end kit from PST, and the 0.96 torsion bars for my 72 Cuda. 3 days ago I removed the old torsion bars with much ease. I removed them at the same time as removing the lower control arms (all parts moving towards the back of the car.) Posts in the forum had led me to believe that removal of the TBs was a real chore, so I was surprised that they came out so easy. I have some Qs of my own:

1) what is a torque box that cuda 2002 is referring to?

2) I have a bent strut rod. Who sells new ones? not PST

3) What is the correct resto color that I should paint the Lower C Arm and the Upper A Frame, etc as I put this all back together?

4) I have no real driving time on this car so don't know the steering box condition. Should I have the power steer box rebuilt while all is apart? Vendor?

Thanks for your answers!

Tim Eckert
72 Cuda 360/904
Concord NC
eckertt@epri.com

[George G. Leverette]

The most cost effective way of stiffening the body is with frame connectors they are a reasonable cost through the dealers. I have been using the Urethane stuff but the cost over stock replacement is not justifiable. Would recommend MOOG improved. If you just gotta have the polly molly stuff use OEM in the lower control arms. .925 Torsion bars P5249157 is the max spring rate (108#) is the maximum I would recommend for your E-body. A level 1 power steering unit from Firm Feel should be added. C-body tie rods and sleeves should also be added.
Performance Handling for Classic Mopars by Tom Condran is a must have suspension book.

[jasontlit]

I have a level II firm feel power steering box with a stock 2 spoke steering wheel.

It is still a bit too loose for me.

Next time I need a steering box it will be the level III. Plus, I'm looking to get a smaller steering wheel to help with the feel.

Most old Mop's I've ever driven with power steering were WAY over assisted for my taste. If you haven't driven one lately...it is like stirring soup with a fork.

[ehostler]

I wouldn't bother with the MP frame connectors. They may be cheap, however, they are of the bolt in design (no good).

You would be tter off having a good body shop fabricate a pair out of square stock and then have them welded in. BigBlockDart.com has a great section on just this.

[cuda2002]

Hi eckertt@epri.co,

to answer your question 1)., check out the recent Feb 2004 Mopar Action article on p. 46 entitled "Torqued Up" (I'll never figure out why a magazine issued in November is dated for Feb!?!). It explains that "torque boxes" are welded between the front and rear sub frame rails and rocker boxes (main frame members). Apparently this was done on convertibles, cop cars and hemi cars to increase frame rigidity at these points.

They give www.autorust.com and www.autospecialt.com as sources for the torque box parts and frame rust repair pieces.

As these companies are supplying these parts, I assume that there is a market and people are using and installing them. I am curious to find out what kind of performance improvement could be made and are there any associated downsides to doing this.

Cheers!!

[pro69bee]

Mopar bolt in conectors worked very well in my aplication.Fit like a glove.Just follow directions and drill holes as small as possible.Dont over tighten lock nuts.You could could go one better and cut pieces of pipe to put between frame sections to tighten more with out crushing frame, drill hole on bottom and insert with suplied bolts.You can even weld them on too. Bolted and welded is the best for extreme use.

[dwc43]

Originally posted by cuda2002
I have a 73 'Cuda that I am building. The car came with a '69 383 which I have done some work on, it was originally a 318 car. The body work is near complete and I want to turn my attention to the suspension. The suspension as far as I am aware is stock and of course 30 years old.

Although I do want the car to be fast in a straight line, the fact is that I will be driving this car regularly and I want it to handle much better (even with the big block); more like a modern car . The car has power steering, front discs and front and rear sway bars.

I am looking for a good reference source so I can do some reading before I jump into making any major changes. I see in the recent Mopar Action magazine that the addition of torque boxes may be a consideration. Apparently, these torque boxes were used on cop cars, convertibles and hemi cars (no mention of the AAR and TA's). Sounds like this was done for both handling high torque engines as well as improve handling, stiffness.

I've been toying with the following ideas: going to 17" wheels with 235 R45's in the front and 265 R45's in the rear. New heavy duty rear springs, polygraphite front rebuild kit, maybe adding the torque boxes. Phase 2 might be tubular control arms,rear discs, bigger torsion bars and sway bars? depending on how hard my budget gets hit.

I want to know what will give me the biggest bang for my buck and what to avoid because of other potential problems it might cause. Any reference books or advise from anyone who has done this would be greatly appreciated.

Thanks in advance.

Here's what you need to make it handle well. First add torsion bars and rear leafs that are only one size bigger than stock. Mopars like softer springs and bars, but they like huge sway bars with an agressive shock package. Dont buy kyb shocks. They are not much betterthan any over the counter gas shock. You need an agressive shock from Carrera,Pro, or Affco.

On sway bars install a 1 1/8 front bar with a 1` inch rear bar. Also add in a set of subframe connectors. The torque boxes want help much. THe are made for restore purposes.

Also dont go to 16 and up wheels either. The profile tires required to get them under the fenders wont be very wide and the slip angle created by them will reduce handling. Matter of fact they will break loose quickly and most of the time they will be unpredictable when they do break loose since the slip angle is exceeded too easly. A 235 to a 255 front tire and a 275 60 rear tire all in 15's will give the best handling and they will be more predictable while performance driving.

As for tube A arms,shocks,and rear disc kits we can fix you up with those parts. How about 450 for a rear disc set up. Cant beat that and it's Wilwoods finest pieces too. The tube A arms require a slight mod, but they use solid bushings to prevent flexing. We also have mono balls for the leaf springs. Solid heim type joints if you will. I can even get you a light weight steel race wheel if you want to go that route too. If you have any questions or need something send me an e mail at dwc4343@homail.com I'll help you out with info or parts. We have set up a many oval track and road course cars before and we know how to make them handle. Matter of fact we are working on our NASCAR Sportsman car now. Trying to get it ready for next year.

[dwc43]

[QUOTE][i]Originally posted by eckertt@epri.co

2) I have a bent strut rod. Who sells new ones? not PST
#1 LAysons has the new aluminum strut rod.

3) What is the correct resto color that I should paint the Lower C Arm and the Upper A Frame, etc as I put this all back together?

#2 Most were left unpainted and allowed to rust and some were painted semi gloss black. So either way is correct.

4) I have no real driving time on this car so don't know the steering box condition. Should I have the power steer box rebuilt while all is apart? Vendor?

#3 Yes, get one from firm feel. www.firmfeel.com

[pro69bee]

NO one makes decent performance handling tires in 15 inch in sizes to fit large cars anymore . I Had the chance to try 17s on my car once ,offset in rear was wrong ,looked funny, too much positive offset, however steering was incredible.Bfgoodrich TAs do not even compare.Much Less lean on corners,smoother ride,on center feel fantastic and seemed to aproach triple digits faster too, less rolling resistance was noted.I do know what im taking about ,alighnment specialist at dealer.275 60s have so much tire side wal flex its pitiful.

[ehostler]

Originally posted by pro69bee
Mopar bolt in conectors worked very well in my aplication.Fit like a glove.Just follow directions and drill holes as small as possible.Dont over tighten lock nuts.You could could go one better and cut pieces of pipe to put between frame sections to tighten more with out crushing frame, drill hole on bottom and insert with suplied bolts.You can even weld them on too. Bolted and welded is the best for extreme use.

Bolt in will eventually turn to trash. The holes that you drill into the frame will begin to oval out and the connectors will start moving around. Weld in is the best way to go.

[pro69bee]

Cant say Ive had that problem.You must have done somthing wrong.

[ehostler]

Nope, I've just never used the bolt in as they are no good.

If yours haven't begun to oval out yet, then you either don't drive the car hard enough to really need the subframe connectors, you haven't put many miles on it since the installation of the connectors, or you just haven't looked to see the problem.

[dwc43]

Originally posted by pro69bee
NO one makes decent performance handling tires in 15 inch in sizes to fit large cars anymore . I Had the chance to try 17s on my car once ,offset in rear was wrong ,looked funny, too much positive offset, however steering was incredible.Bfgoodrich TAs do not even compare.Much Less lean on corners,smoother ride,on center feel fantastic and seemed to aproach triple digits faster too, less rolling resistance was noted.I do know what im taking about ,alighnment specialist at dealer.275 60s have so much tire side wal flex its pitiful.

Your incorrect. I know we deal with tires every day. We run NASCAR Sportsman on racing tires and street tires on our front runner. BF TA's, Michelin Pilots, Yokahoma, there are many tires that preform today. 275 60's if mounted on the proper wheel and with proper pressure do NOT flex to much. You have to have a certain amount of flex to achieve the proper slip angles for the best cornering traction 16's up and 50 series or less do not handle as well. THey have less slip angle and give up rather quickly and some times very unpredictably too. That's the facts.

[dwc43]

Originally posted by ehostler
Bolt in will eventually turn to trash. The holes that you drill into the frame will begin to oval out and the connectors will start moving around. Weld in is the best way to go.

I agree there E. We build our own and we have welded in the bolt in type for other people too.

[dan d rat]

just susspention carries strut rods. i don't have there phone number on hand but they advertise in mopar mucle all the time so you can look there for there phone number.
i bought some hd strut rods from them and although i have yet to put them in i can tell you that there about twice as thick as my old bent ones. i hope that helps.

[eckertt@epri.co]

dwc43

thanks for you answers and the tip to firmfeel.

Tim Eckert

72 Cuda 360/904

[dwc43]

Welcome, anytime.

[cuda2002]

Originally posted by dwc43
Here's what you need to make it handle well. First add torsion bars and rear leafs that are only one size bigger than stock. Mopars like softer springs and bars, but they like huge sway bars with an agressive shock package. Dont buy kyb shocks. They are not much betterthan any over the counter gas shock. You need an agressive shock from Carrera,Pro, or Affco.

On sway bars install a 1 1/8 front bar with a 1` inch rear bar. Also add in a set of subframe connectors. The torque boxes want help much. THe are made for restore purposes.

Also dont go to 16 and up wheels either. The profile tires required to get them under the fenders wont be very wide and the slip angle created by them will reduce handling. Matter of fact they will break loose quickly and most of the time they will be unpredictable when they do break loose since the slip angle is exceeded too easly. A 235 to a 255 front tire and a 275 60 rear tire all in 15's will give the best handling and they will be more predictable while performance driving.

As for tube A arms,shocks,and rear disc kits we can fix you up with those parts. How about 450 for a rear disc set up. Cant beat that and it's Wilwoods finest pieces too. The tube A arms require a slight mod, but they use solid bushings to prevent flexing. We also have mono balls for the leaf springs. Solid heim type joints if you will. I can even get you a light weight steel race wheel if you want to go that route too. If you have any questions or need something send me an e mail at dwc4343@homail.com I'll help you out with info or parts. We have set up a many oval track and road course cars before and we know how to make them handle. Matter of fact we are working on our NASCAR Sportsman car now. Trying to get it ready for next year.

Thanks for the info dwc43.

As I haven't done alot of reading on suspension and chasis set-up yet, maybe you could elaborate on the tire size for me. I understand that going to a larger rim size would effectively reduce the sidewall height if I want it to fit in the existing wheel wells. I would have thought that a lower profile (stiffer side wall) would give better handling than a bigger side wall (ie. mushier). I would agree that it maybe somewhat more unpredictable on when it breaks free but I would think you would be able to push it further.

Also, could you elaborate on the sub frame connectors vs torque boxes (or is it vs. torque boxes). Your thoughts would be greatly appreciated.

[dwc43]

Well for one a low profile 50 or less tire has less slip angle. It does not face the road correctly during cornering. IT will over heat under cornering faster and it will break loose when you need it too the least with very little driver input. I know I have tested some 50's and almost looped it then tried the 60 and it went faster without being loose.

Plus remeber this about tires. They act like springs. Well at least the radials do. With radials air changes will only get you a 1/4 inch change in stagger in either direction. Now the bias tires would grow or shrink quite a bit with air pressure changes so you could change the stagger with an air change to affect handling.

Back to the spring part. On an oval track left turn only if you put too much right front spring in it , it will push. Too much air it will push. Too short a side wall it will push. The tires act like the springs in this example. Less air will let it flex and it acts like you reduced the spring rate on that wheel and vise versa. Too short a side wall wont let it flex enough and it makes it act like a stiffer spring rate, plus with the shorter side wall air pressure changes will have less of an effect on it handling wise.

Subframes connecter are better than torque boxes. They transfer more load under cornering. If you really want the best set up for racing or cornering install an X between the sub frames. It transfers more load and prevents chassis flex even better than the subframe connectors do.

[George G. Leverette]

I "use" not guess at the effect of the Mopar frame connectors, they are the most cost effective improvement that can be made to the suspension system. Follow Mopars instructions and bolt the frame connectors in, then run down to the muffler shop and have them welded in or weld them in yourself if you have the expertise. After installation the effect can be noticed immediately, when jacking the car from the side the body flex is eleminated the entire side of the car will raise whether the jack is at the front or rear jackink location. For those occasional strip forays this should aid the 60 ft times. I have two sets on my cars now and will be installing a set on another A-body, these frame connectors are highly recommended.

[George G. Leverette]

dwc43 I havew been wondering about the comments of 50 vs 60 series tires. It appears from a physics point of view that a 50 series tire will have more contact with the surface for a given height If the contact patch is greater then the co-efficent of friction would be greater meaning the 50 series tire will stay in contact with surface longer. It also appears that modern cars are going to lower profiles, my wifes 04 PT Cruiser has 18" wheels with 40 series tires to improve handling, the tires are also Z rated with A temperature rating. Are you saying that with old suspensions that 60 series are better or what its confusing to me.

[moparmotorman]

60's happen to be my preferance as well. I have 275/60 on the rear and 225/70 on the front, I like the look, but the car also handles great and rides nice. I bought the leafsprings from ESPO 1" over stock height, and .960 MP torsion bars and KYB shocks all around, rubber bushings on contolarms and poly bushings on strutrods and front and rear swaybars. DWCS, how much air would you put in rear tires? I have firestone indy 500's and they say I can put 45 psi, that sounds high to me , what do you think?? Right now I run 32 psi all around.

[pro69bee]

Dcw3 ,You are wrong .I have drove too many different types of cars and tires too believe you . Circle track is not even street.Those circle track tires have a carcass like NEW plus sized tires and are much lighter to boot. Mopar conectors are the lightest and best enginered ,and can be welded very efectively for hard drivers.

[dwc43]

Originally posted by George G. Leverette
dwc43 I havew been wondering about the comments of 50 vs 60 series tires. It appears from a physics point of view that a 50 series tire will have more contact with the surface for a given height If the contact patch is greater then the co-efficent of friction would be greater meaning the 50 series tire will stay in contact with surface longer. It also appears that modern cars are going to lower profiles, my wifes 04 PT Cruiser has 18" wheels with 40 series tires to improve handling, the tires are also Z rated with A temperature rating. Are you saying that with old suspensions that 60 series are better or what its confusing to me.

It depends on size as to what your contact patch will be. Taller as well as wider will increase contact patch. Of course wider gets you more than taller will if this makes since. The 50's give a harsher ride and good traction at lower speeds, but not at higher speeds during cornering because you cant create the slip angle you need with them. I belive most of the info I have given you can be read in a book called ' How to make your car Handle" by Herb Adams I believe. See if you can get a copy to read. He explains it much better than I ever can.

[dwc43]

Originally posted by moparmotorman
60's happen to be my preferance as well. I have 275/60 on the rear and 225/70 on the front, I like the look, but the car also handles great and rides nice. I bought the leafsprings from ESPO 1" over stock height, and .960 MP torsion bars and KYB shocks all around, rubber bushings on contolarms and poly bushings on strutrods and front and rear swaybars. DWCS, how much air would you put in rear tires? I have firestone indy 500's and they say I can put 45 psi, that sounds high to me , what do you think?? Right now I run 32 psi all around.

Depends. Rim width will make a difference. Start out with 35 and see how you like the traction and watch the middle of the tire. If it starts to wear in the middle it's got too much air in it. If you have a infared pyrometer measure the tire in the middle and the two out side edges. If the middle is constanly the hotest one then it's got too much air in it.

[moparmotorman]

air pressure tip sounds good, i'll do a mild burnout and check the stripes. I've also found that street radials hook up better with higher pressure rather than lower like a slick or drag radial. Whatcha think??