Suspension

[Ratvon]

I want to put the best handling street and strip suspension in my 70 challenger and would like to hear pros and cons of what everyone has! I dont want to cut or weld something on the car that can't be cut off or put back to original. I want better handling and better braking and nothing made with China steel. Hopefully putting in a 392 plug and play

 

[fasjac]

I think I’d look at QA1, Alterkation and maybe Freak suspension. I don’t know if there’s a kit available for the late hemi to fit with your stock K member or not. There probably is since guys have been doing this for a while now. I personally would upgrade rear leaf springs, shocks and sway bar etc, other than something like a 4 link. Anything you weld on can obviously be cut off and put back to factory. JMO sorry I haven’t done this to my cuda but, I had the pleasure of working on my bosses cuda that had the Freak suspension and coil overs, rack and 4 link in the rear. It handled fantastic! Car had a supercharged Kenne bell on the 6.1 hemi.
Good luck to you and please share the build with us. I’m personally kicking around something similar to what you’re wanting.

 

[Chryco Psycho]

Firm Feel , QA1 , Hotchkiss, all offer upgrades
You can take a Mopar past 1g cornering without changing the basic design of the suspension , it was well designed for 1970 , just upgrading the parts involved .
Chassis stiffening has a lot to do with cornering & almost 50% of the cornering improvement comes from just the wheels & tires used , unsprung weight is also very important .
SO I would start with bracing the K frame or replacing it with a QA1 K frame & brace the lower control arms as well as the inner fender braces & lower rad support , factory torque boxes front & rear , subframe connectors etc to stiffen the body up.
Then improve the suspension with balanced upgraded spring rates front & rear , composite rear leaf springs for lighter weight & better spring rate , larger T bars in front & double adjustable shocks front & rear , , you can use modified stock upper control arms or fully adjustable uppers but you will have to replace rod ends regularly . You can use the adjustable lower strut rods , bigger C body tierods & sleeves . You can also increase the sway bars in size & use hollow bars this reduces weight & increases the roll stiffness , I feel increasing the sway bar stiffness is far more important over increased spring rates , increased spring rates can cause the tire to bounce off the pavement where increased sway bar diameter & good shock will keep the tire under control on the pavement . Little known fact but the leaf spring as it flattens on the load side moves the diff rearward & actually helps to steer the car in corners , coil overs & 4 links cannot do this .
You can also use the Borgeson steering box or a firm feel or Steer & Gear stage 3 for better feel .
Keeping the weight low , keeping the leaf springs close to flat , & keeping as much weight in the center of the car & getting close to 50/50 weight distribution all help also .

 

[Max Wedge]

A bit of a ramble coming here:

Suggestion: Don't go crazy with spring rates or mods until the body is stiffened. Otherwise, the body will act as a fifth spring and undermine anything else you do.

The factory Trans Am cars are a good object lesson. More or less factory configuration (although nothing stock as we know it), plus quad shocks on the rear of the Plymouths and a panhard bar. It worked. I don't think I'd abandon the stock arrangement until I was getting really fast. JMHO.

I know Gurney/Autodynamics modified the UCA mounts to reduce anti-dive and improve camber curve, but specs on that are elusive.

I think the amount of anti-dive we have built in is excessive for anything but a cruiser or grocery-getter with soft springs (which is what most cars were). It's also the reason we need so much caster to keep it from going positive on the inner tire on a heavy curve. Especially with the front spindle being relatively short. Caster change under jounce/rebound is big compared to others, and the reason you see such tall spindles on newer cars. (Looking at the Hotchkis front suspension and UCA, I assume they feel the same way)


My setup thus far:

Factory Rallye rear swaybar was a big improvement on my factory type XHD suspension. Looks factory because it is. Frame hung for minimum unsprung weight, cleared my TTI 3" pipes. Firm Feel has equivalents and sold me the spring plates alone.

I used poly bushings for the swaybar links, and offset Moog control arm bushings.

I used rubber bushings elsewhere because people confuse rattling teeth with good handling (My opinion. YMMV).

QA1 double adjustable shocks work well also and give you 8 knobs to play with forever...track adjustable for any purpose as well - good stuff.

73 up spindles offer marginally better geometry, large bearings and can mount 11.75" cop discs with pin type calipers.

Firm Feel lower control arm reinforcement plates are worthwhile esp. with a heavier front bar.

Nothing exotic so far. If I lost some front end weight it would be about as good as my 88 Diplomat cop car was, and that was pretty good for what it was.

I'd go with heavier front torsion bars at some point, but I need to put in subframe connectors and hemi torque boxes to make it worthwhile. Parts on shelf and on the list of to-do's.

 

[70chall440]

First thing fist, you have to decide how you are going to use the car. A good street or road race suspension is not a good drag race suspension but you said you want it to handle so I am "assuming" you want better road manners for spirited driving rather than a drag race config?

With this said, Chryro gave you some excellent advice which is worth heeding. There are a few options out there, to the point that it can be somewhat confusing so I will give you my thoughts on this since I have installed quite a bit of suspension and am in the process of doing several more.

There are a few "kits" out there like those from QA1 and Hotchkiss. They do work and perform but there are other options. What I do is develop a matrix and look at all of the various components I need, then select the best ones (in my opinion) to do the job.

Steering box - as mentioned you can use a Borgeson, Firm Feel or perhaps a R&P system (if you are changing the K frame to a tubular). I have 2 Firm Feel stage 3 boxes with their fast ratio idler/pitman arms and they are awesome. I am going to be using a Borgeson box in my 71 Charger with my 5.7 because I want to try one along with a Holley PS pump. One issue here is that you need to match the PS pump with the box; if you put that modern hemi pump on a factory box you may have some issues due to the increased pressure.

UCAs - I really like tubular UCAs and normally use Firm Feel's, they are simple and effective. While some of the other ones out there provide all sorts of adjustment, I personally feel that unless you are actually road racing you probably do not need all that adjustment, its just one more thing to mess with and get wrong.

LCAs - I always use the factory ones but I box them in. I don't like the tubular LCAs personally but I am sure they work (for awhile).

Bushings - I buy a full poly kit from Firm Feel but you can get them from other places like PST

Front sway bar - Look at the Hotchkiss or firm feel bar

Rear sway bar - I like the Hotchkiss bar

T bars - 1.14 if you want it really handle but you can go slightly smaller if you are concerned about the ride

Leaf springs - look at the Hotchkiss springs

Shocks - this is one of the biggest decisions and your selection will have perhaps the biggest impact on the end result. You need GOOD shocks such as Bilstein's or QA1. Look hard at the double adjustable.

Now with all this said we come to the area you don't want to go and that is bracing. If you really want the car to handle, it needs to be tight and from the factory these cars were not. I put full sub frame connectors, under fender braces and lower radiator braces on all my cars. The result of just this effort is tremendous however these are not "bolt in", they generally must be welded in (although there are some bolt in sub frame connectors). I use the US Car Tool "fitted" sub frame connectors and once in look like they belong there.

Last item is wheels/tires and given the huge assortment available I will just say that you need good tires for all of this suspension to work well.

 

[Ratvon]

I like everyone's opinions and ideas and will use them all to come up with what I want!
I been a drag racer for about 40 years. But how cool would it be to show up at a roadtrack race with a 70 Challenger! I just in the planning stages don't know what direction I'm going.