I'm considering the pros and cons of leaf springs vs 4 link rear suspension for when I do my Challenger project. What are some advantages of the 4 link vs leaf springs, or vice versa? The new Challenger has a 5 link rear suspension, so I'm assuming that type of system can work better?

The new Challenger also has independent rear suspension. And it has a myriad of criteria and constraints that you will not have.


There is more than one way to get to the same place.


Really need more info from you on what you want. And what other relevant constraints you project might have. Like is there a super wide rear wheel you have to have that's going to require mini or full tubbing? Are you looking to the extra bling or custom visual impact of 4 link tubular rear? ect.

What are your end use performance goals?

Are you looking for value?
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The "serious" Mopar track cars and autox cars that I'm aware of run leaf springs and torsion bars. There might be a lot of different reasons for that, but I just don't recall seeing many serious track efforts with coil overs or multi-link suspensions. The stock Mopar suspension is simple and strong and has decent geometry.

Leaf springs are great until you reach a torque/traction threshold. Then they either need ditched or a Caltrac type device added. If anyone wants some leafs tested send them my way.

You've got mini tubs? wide 315/35/18 grippy rear tires, and had a 451? before?

NASCAR ran leafs for years and so did Trans Am. Hardly anyone builds Mopar track cars today that are faster than the old Trans Am cars. I watched Tim hold his own against Vipers and Z06's at the track for race after race. That old red Valiant just had stock 340 rear leafs on it. 500+ ft-lbs of torque corner after corner, race after race.

Another way to answer the question is to find out what oil pan you're planning to run. If you have a wet sump system then the leaf springs and torsion bar suspension will work just fine. If you have a dry sump setup then you might be able to justify a more sophisticated suspension.

One other approach is to figure how good of a driver you are. You have to be a really good driver to exceed the limits of the torsion bar and leaf spring setup. Very few non-pro drivers can push past the limits of a well setup leaf and torsion bar suspension.

Leafs have a limit in wrap vs. rate in my experience. If they have no wrap, then they have a bunch of rate. Those Trans Am and Nascars had BEEFY 200+lb springs.

If I was building a clean sheet race Valiant, I'd go to a 3-link rear instead of leafs.

Not necessarily that big of a trade off.

The geometry of the leafs help a bunch. That short stiff front segment controls the wrap while the long thin rear segment controls the ride. That's a pretty generic description but true until you get into heavy compression.

What it means is that you can control wrap separate from ride.

Few manufacturers of leaf sprung cars have bothered to optimize it. Most of them have front and rear segment lengths that are the same and then try to control wrap up using extra segments in the front or higher rates, or both.

As for spring rates in NASCAR, not a good example. Downforce plays a huge role compared to anything most of us drive affection rear spring rates there.

Tim's car was very fast with just stock leaf springs. I think that Eberg added a pair of kicker shocks on the Brick to control wrap up. Spring wrap up doesn't seem like a huge problem to me since I haven't seen very many Mopars that get around a track faster than either the Brick or Tim's Valiant.

Mopar leaf springs are a fairly complex animal with spring rate, load rate, and control ratio all factors in getting the right set up in the spring. However, spec those three requirements to your specific vehicle, and you can have a pretty well engineered leaf spring.

FWIW, there are not any off the shelf leaf springs that can specifically address all those factors for every car. They can narrow it down significantly by building spring sets by body style to get it closer, which will suit 95% of the drivers out there, but to truly dial in those three parameters require a custom spring.

Still is, although probably not with me behind the wheel! The thing that is interesting about the Valiant is that the front is very stiff, but the rear suspension is very soft by comparison.

Some of that is physics, some of it was driver's preference. Last time I scaled that car I think it was still 55/45 front to rear weight. The aluminum heads helped a bunch but the race block is super heavy. With most of the weight on the front tires the springs have to match.

We tried stiffer rear springs (still have some sitting out in the shop) but Tim went back to the old 340 springs since they worked the best.

I can very well be guilty of wanting a road course car that withstands a Ronnie Sox impression at will. I don't like laying into the throttle to be mandatory.

Dang... 55/45

Best for me so far is 57/43. Hopefully aluminum cased 4 spd vs automatic, heater core removal, auto console removal, borgenson steering box and aluminum p/s pump will get me close(r).

Just got a set of Intercomp scales for $250. So I've got something handy to play with.

3209 lbs?


Must be nice.

Yep. Thanks. But still a long way to go.

No driver, no spare tire, no carpeted trunk mat.

Last info I have on Tim's car was 3100 lbs and 55/45 front to rear. But he pulled some more weight out of after that so I don't know how it sits today.