Auto-X / Roadrace rear suspension 1969 Valiant

Hi guys, I don't have too much to add here, but geometry and ride quality may play into your decision making. I like things super quiet and smooth, so my options may vary.

The reality of available parts vs theory is also part of this. The one guy who could supply composite leafs is out of business. I've tried all the AFCO springs without success.

The roller shackle is interesting, but I'd bet it makes a hell of a racket. This is similar to any torque arm style rear setup.

The AFCO spring notes are interesting, but their parts are geared to oval tracks. Also remember, the amount of roll is partially dependent on the distance of the roll center to the center of gravity. This is why raising the rear height is instant destruction to handling on any leaf spring vehicle.

Lastly, the Mopar road race manuals suggested raising the front eye position where possible. The flatter the mounting points, the more neutral the toe steer will be.

Having many open track days under my belt, I can say that stabilizing the spring laterally is of great importance. I destroyed shackles by side loading them. The pins, if they are the old MP ones, should be welded in place to avoid wallowing out the holes in the side plate.

Once again, if you were thinking about an aftermarket suspension for the back, I wouldn't consider anything else than the DSE Gen X. I will most likely be doing this on my Dart in the future. If I do, and have to make specific parts for them to fit, I would do so.

I recently moved to NC from a lifetime in NY and am finishing up a new building as we speak. 2023 will be a fun year as a result.