Ask Away! with Jeff Smith: Suspension Upgrade Tips for Early Chevelles (and other A-Bodies)

I just purchased a ’64 Chevelle that is very close to stock. It has a 350-cubic-inch small block and a Turbo 350 that I’m happy with, so I’m thinking of improving the handling but only if I can do that without making it ride like a dump truck. I’ve seen rear sway bars on many Chevelles and wonder if that’s where I should start to make my car handle better?

T.M.

Jeff Smith: Let’s start by talking about the stock Chevelle suspension and its weak points. Then we can begin to look at basic changes that will improve the handling without destroying the ride quality. The front suspension on the Chevelle is very similar to the early Camaro in its weak points. The spindle height is very short, which means that when the car enters a left-hand corner for example, the body will roll, compressing the right side, placing much of the load on the right front corner. Because of the spindle height and control arm placement, the suspension under compression will always produce a positive camber gain. In other words, if the static camber setting was zero (looking at the car from the front, the tire would be straight up and down), under several degrees of roll, the right front will move roughly 2 or 3 degrees of positive camber. This means that the top of the tire will tilt outward which tends to accentuate pushing the tire out from under the car under hard cornering. As a result, the car will experience understeer – commonly called “push” or plow.

GM designed the suspension to do this because understeer tends to be more easily recoverable than oversteer, which is when the tail of the car comes around. Oversteer is more controllable for a competent driver, but all the OE’s chose to build their cars to produce understeer. This understeer is produced by a combination of weak front springs, soft shocks, and a very small anti-roll bar. Stiffening any or all of these components will tend to produce less body roll, which reduces the amount of positive camber gain. This tends to make the car respond better at slightly higher cornering speeds. Certainly better tires – with more grip – will also improve this situation.

Before we get into all the cool modifications, let’s hit the safety thing first. You’re working with a car that has been on the road for 50 years – yikes. It’s likely the ball joints, upper and lower control arm bushings, and tie rod ends have never been changed and are worn out. In the case of early Chevelles, the drag link is also critical as it contains a wear point and probably needs to be replaced. Before you think about performance changes, the stock suspension must be in good shape – that’s a given. Of course, if bushings need replaced and you plan to keep the car, I always recommend using Global West’s Del-A-Lum bushings. These do not hurt ride quality, they will last forever, and they don’t deflect like rubber.

The next point is that early Chevelles are famous for cracks forming in the lower control arm near the lower ball joint. Check your car now – especially the trailing side of the passenger side lower arm. This is very common – I’ve discovered major cracks in two of my Chevelles and also on a close friend’s El Camino. His lower arm broke in a parking lot just as he was about to drive on the freeway. Imagine if the lower control arm failed at 70 miles-per-hour – it would have been ugly! Check your car now and if the control arm is cracked – replace it with a new one and don’t drive the car until you do.

With a stock front suspension, adding a rear sway bar tends to reduce body roll slightly, so by stiffening the rear suspension, this reduces body roll and induces less positive camber gain. If you combine this with a much larger front sway bar of 1-inch to 1 1/8-inch along with a set of performance shock absorbers on all four corners, this will drastically improve the handling. I would also recommend increasing the front spring rate at the same time. The stock Chevelle small-block spring rate is somewhere around 300 pounds per inch (lbs./in.). This means it requires 300 pounds of load to compress the spring one inch. My suggestion would be to increase the rate to around 500 to 600 lbs./in. This is a major increase but it will result in a drastic improvement in limiting the front body roll. Do not be afraid of high spring rates. Shock absorber valving has a much greater effect on ride quality than spring rate. Combined with larger front anti-roll bars and adjustable shocks, this will help to control the positive camber gain without killing the ride quality.

There are several companies with packages you can buy that have already done all of this tuning work for you. But if you do some scrounging, you can improve handling without spending a ton of money. That leaves some coin left over for shocks, tires, and wheels where it will do the most good. For example, a second-generation Camaro or Firebird front sway bar will bolt right on to an early Chevelle and these bars are generally larger than the stock Chevelle bars.

Companies that make entire Chevelle systems include Global West, Hotchkis, Detroit Speed, Ridetech, QA1 and others. Ridetech for example, just created a line called StreetGrip that offers individual components like springs, sway bars, and adjustable shocks or the complete package for $2,000. The beauty of any of these kits is that you can build them a piece at a time if that’s all your budget will allow.

As an example of how to improve the handling, adding a 1-inch taller spindle from a late ‘70s Impala or a second-generation Camaro will drastically alter that camber curve from gaining positive camber to gaining negative camber. That makes a huge difference in handling improvement. Another trick you can try that is far less invasive is a taller upper ball joint that somewhat accomplishes the same effect. Ridetech offers a taller upper ball joint (PN 90000894) that will improve the camber curve while not sacrificing your existing brake package. If you add a taller spindle, you will need to add a tubular upper control arm from Global West, Hotchkis, or one of the other companies. This will produce a superior camber curve and better control the caster. I highly recommend this if you go to a taller spindle.

If your car is as untouched as you say, it’s possible that the Chevelle is still equipped with front drum brakes. You might want to consider an upgrade there as well. In this case, the simplest thing might be to convert to a ’68-72 Chevelle disc brake system up front while retaining the rear drums. This can be as simple as bolting on a ’68-’72 Chevelle spindle and then using the stock 11-inch front disc brakes and floating single-piston caliper. This is an easy conversion although we would recommend using a dual-reservoir master cylinder in addition to an adjustable rear brake proportioning valve so you can reduce the pressure to the rear brakes to avoid premature lock-up.

As you can see, there are a ton of options. It’s probably best to seek out some Chevelle owners and ask them which package they prefer and perhaps take a ride in their car with their changes. I have three ’64-’65-’66 Chevelles/El Caminos all with different suspension packages based on the car’s intended purpose. Each is completely different than the others so there are literally dozens of different ways to outfit your Chevelle. Take your time, do some investigating, and then make a decision.

Here are some final thoughts:

The biggest improvement in handling will be with tires and wheels. A shorter sidewall will respond quicker and handle better but negatively affect the ride quality. Shocks are next in line in terms of affecting overall ride quality – I would highly recommend adjustable shocks to allow changes to handling as you add different packages. The other key is to carefully integrate your parts so they work together – or just follow the package created by the manufacturer. That will get you closer to your goal with less frustration.