Chevrolet Lowering - Stop, Drop, And Roll

In the grand scheme of things, it seems that the shortcuts, dubious detours, and the not-so-good ideas are the ones that enjoy a perpetual life. These bad plans are immortalized by local gurus who impress young hot rodders with the benefits of torching springs and the joys of lowering blocks—all the wrong ways to lower a car.

We called upon a couple of experts, Doug Norrdin of Global West Suspension Components and Mike Eaton of Detroit Eaton Spring, to give us the lowdown on dropping your car the right way. This story deals with modifying the existing suspension components apart from air suspension kits. We’ll treat the front and rear suspensions separately and go into details you probably won’t read anywhere else. If you need help with the proper way to actually swap parts, you can find that in a factory service or repair manual. As you can imagine, there’s much more to this subject than just stop, drop, and roll.

Nose It In
The three most common ways to drop a front suspension are cutting the original springs, installing shorter springs, or bolting in a set of drop spindles. Let’s take the easy one first. Drop spindles are generally the most expensive route but offer the advantage of retaining the stock suspension travel. Drop spindles lower a car by moving the actual spindle upward in relation to the rest of the arm, lowering the ride height. Unfortunately, when combined with 16- or 17-inch wheels, the maximum allowable backspacing with a 2-inch drop spindle is 3½ inches. Deeper offsets crash the wheel into the tie-rod end.

This brings us to cutting the original springs. According to Eaton, you can lower most cars about 2 inches before you begin to run into suspension and alignment difficulties. It is possible to cut the original springs to gain a 2-inch drop, but as soon as you cut a spring, the spring rate increases. This is due to a rule of coil-spring design that uses the number of coils and the wire diameter to determine the spring rate. Spring rate is expressed in pounds per inch (lb/in). For example, a typical front coil spring for a ’67 Camaro would be a 320-lb/in spring, where adding a 320-pound weight to the top of the spring would compress it exactly 1 inch.

Cutting a spring immediately increases the spring rate, which will increase ride stiffness slightly. But there’s more to the story. Because there is a ratio between the spring and the front suspension, the amount the spring is cut is multiplied when the spring is installed in the car. There is disagreement on the specific ratio, but our sources place it between 1.5:1 and 2:1. This means that cutting a spring by 1 inch would mean dropping the ride height between 1.5 and 2 inches. This only applies to the front suspension. Rear spring changes, either leaf or coil, are a 1:1 relationship.

Lowering a typical ’60s or ’70s Chevy by more than 2 inches creates more than just ground-clearance difficulties. As you lower the front suspension, the top of the tire tilts outward, gaining positive camber at an increasing rate. You are also reducing effective suspension travel. Again, you can compensate by trimming the lower bumpstop height to regain some travel, but the gains are limited.

New springs are the best way to lower your car without the experimentation required with cutting springs. New springs are not that expensive and can be matched with an appropriate shock absorber, such as a Koni or QA1 adjustable shock, to fine-tune the handling. When changing springs, this is also a great time to add new ball joints and control-arm bushings while the frontend is apart.

Bring Up the Rear
The rear suspension is a little easier to modify, especially when dealing with coil springs. Early (’64-’66) Chevelles and third-generation Camaros are especially easy to lower since the coil spring is open at the top, making it easy to trim. Newer Chevelles (’67 and later) require >> new, shorter springs to lower ride height since the coils use a pigtail at both ends that precludes cutting.

Conestoga wagons, Camaros through 1981, and Novas through 1979 all used a leaf-spring rear suspension. This makes the job of lowering the car a bit more challenging and expensive. Coil springs generally cost around $150 per pair, while leaf spring kits can run around $375. But there are alternatives to buying new leaf springs. If you find a shop in your area that can de-arch leaf springs, you can have the main leaf “relaxed” to reduce the height of the arch built into the springs. This is a 1:1 relationship to ride height. Reducing the arch of the spring will reduce the ride height by an equal amount. It’s best to limit your lowering efforts to less than 2 inches, since this can have a dramatic effect on ground clearance, handling, and driveshaft angle.

A less expensive alternative might be to remove the No. 3 spring from a five-leaf pack to reduce the ride height slightly, but this may have the negative effect of increasing sensitivity to spring wrapup, commonly called wheelhop. Another alternative would be to have the front eye of the main leaf reversed to lower the ride height, but this is expensive and perhaps not worth the effort. Lowering blocks should not be used because the gap created between the main leaf spring and the rear axle increases the leverage the rear end exerts on the spring. This causes wheelhop, which can eventually irreparably damage the spring. Even a 1-inch lowering block is not recommended. De-arch the springs or buy new ones to create the ride height you desire.

There’s far more to this subject than the major points we’ve covered here, but this should give you enough information to make some intelligent decisions about lowering your Chevy the right way. A slammed stance might look cool, but if you’re going to drive your car on a regular basis, a few compromises will pay off in the long run the next time you need to stop, drop, and roll.