Cal Club Autocross Forums

On that model car, the rear tire is tucked. So, sidewall bulge is a killer.
This car is tubbed, but you can see the tire is tucked.

Bryan Fargo wrote: I was hoping for an easy solution

2x4 under throttle pedal.

I have a set of drag race wheels with drag radials (235-60-15), but the rear end feels like jello going through a corner with them. They dont work very well above 25 psi either. Early Novas are deceivingly small and light for "muscle" cars (3100lbs), although they were the compact economy car of the 60s, not really muscle cars. I have about 10" between my leaf spring and rolled outer fender lip. As Steve mentioned, the rear tire tucks in the fender so I cant run a wider rim and tire combo without a sawzall .

I know some ASP National Champs will do entire runs without ever giving full throttle in their Vettes ...

Make sure you run with your AC on and do whatever else you can to rob power in that thing!

Mako Koiwai wrote:

Bigger Tires

... you'll find lots of worn fender liners among our AX'ing cars ... ;)

Fender liners weren't invented back then for the Nova/Chevy II. ;)

Mako Koiwai wrote:I know some ASP National Champs will do entire runs without ever giving full throttle in their Vettes ...

Make sure you run with your AC on and do whatever else you can to rob power in that thing!

How about a 2 barrel carb???

I'll take some lead out of my foot!

The following are typical leaf spring live axle mods and do help:

1. Panhard bar - as long as possible and as adjustable as possible.
2. Staggered shocks.
3. Cambered housing.
4. Composite rear springs (Hyperco and others).
5. Boxed sliding shackles.

And if you really want to make it work, get rid of the leaf springs and run a three link torque arm with coil overs.

John Coffey wrote:The following are typical leaf spring live axle mods and do help:

1. Panhard bar - as long as possible and as adjustable as possible.
2. Staggered shocks.
3. Cambered housing.
4. Composite rear springs (Hyperco and others).
5. Boxed sliding shackles.

And if you really want to make it work, get rid of the leaf springs and run a three link torque arm with coil overs.

Thanks for the feedback John. In my experience with leaf springs the lateral movement is minimal and does not require a panhard bar. One benefit I was thinking was the panhard bar could be built to raise the rear roll center to induce a bit more understeer. What do you think?

The slider shackles are a nice addition as they help a bit with lateral movement and dont bind up. I currently run urethane leaf spring bushings with short shackles, so I dont feel the sliders will be all that effective.

What benefit do composite rear springs have over spring steel?

I know staggered shocks are used to control axle wrap- how do they affect cornering?

A three link would be nice- its only $$$$!

Every one of the changes I mentioned is an incremental improvement and one, by itself, is not a big deal. Its easy to argue against each one and miss the combined benefits of a whole system approach. Combined they better locate the live axle and make the rear suspension more subtle and responsive. Composite rear springs are lighter and if you run a Panhard bar and take the lateral location duty away from the leaf springs, they can be even lighter and more responsive. You will need to work our some method of handling pinion torque if you go too light on the leaf springs. An aluminum rear axle housing is another good option. The staggered shocks is a hit or miss thing. It works on some cars and drivers and doesn't work on others.

BTW.. something simple as adjusting pinon angle by a degree or two can make a noticeable difference in getting power down.

As others have mentioned ... what about a LSD ?

All muscle cars have an LSD. Its a given.

Mako Koiwai wrote:As others have mentioned ... what about a LSD ?

I have a detroit locker- no limited slip, just locked or unlocked! Its a bit noisy- you will hear a clicking type noise when I go around corners.

John Coffey wrote:Every one of the changes I mentioned is an incremental improvement and one, by itself, is not a big deal. Its easy to argue against each one and miss the combined benefits of a whole system approach. Combined they better locate the live axle and make the rear suspension more subtle and responsive. Composite rear springs are lighter and if you run a Panhard bar and take the lateral location duty away from the leaf springs, they can be even lighter and more responsive. You will need to work our some method of handling pinion torque if you go too light on the leaf springs. An aluminum rear axle housing is another good option. The staggered shocks is a hit or miss thing. It works on some cars and drivers and doesn't work on others.

BTW.. something simple as adjusting pinon angle by a degree or two can make a noticeable difference in getting power down.

I appreciate your feedback John!

This may sound weird, but consider the source.
Change the ratio of accelerator pedal movement to throttle opening. Easiest way is to extend the throttle link arm at carb. Of course make sure you can still achieve full throttle. It doesn't take much of a decrease in ratio to make the throttle less sensitive.
Motorcyclist have been doing this forever especially on motocross bikes. Typically they use a cam shaped throttle twist grip, but it's the same idea.
JP