When independent rear suspension came out in the 1963 Corvette, it was cutting-edge technology that worked so well Chevrolet kept that same basic design all the way through two decades of production. Then, the world moved on to better-controlling rear suspensions featuring replaceable hub assemblies and the equivalent of four-bar rear suspensions.
Many owners of those earlier Corvettes also have late-model equivalents they drive more often, and perhaps more aggressively. Thanks to Detroit Speed and its DECAlink rear suspension assembly, now those earlier examples of Corvette coolness can utilize technologies that not only compare, but surpass those more recent designs.
Detroit Speed has been producing their DECAlink rear suspension for 1963-1982 Corvettes for some time. The one stipulation to installing the system was the body needed to be removed from the frame due to the way the chassis components mounted to the framerails. Now, installing DECAlink can be performed without removing the body and Detroit Speed has released videos showing the process, step-by-step.
Everything pertaining to the DECAlink system mounts to the stout differential cradle, consisting of a two-part, aluminum casting (which greatly simplifies differential changes), thick-walled tubing, and pressed steel reaching out to the mounting locations on the vehicle’s frame. The cradle structure provides rigid suspension mounting and the 2-piece, cast-aluminum differential cradle makes maintenance and differential changes much easier than the stock or aftermarket suspension options currently available.
“Our DECAlink rear suspension has many newly-designed parts to eliminate the typical C2 and C3 weaknesses,” commented Kyle Tucker, owner of Detroit Speed. “The multi-link rear system attaches to the stock rear frame using aluminum castings and a powdercoated tubular crossmember. To achieve the suspension geometry and handling we were after, we designed and manufactured a new aluminum rear upright which we proudly produce in the USA.”
Re-engineering the way which DECAlink mounts to the frame means it can be installed from under the vehicle, without having to access or modify the top-side of the frame. There are a few frame modifications necessary to install the DECAlink system, but we’d bet if you’re looking for the level of performance and handling DECAlink will give your Corvette, numbers-matching isn’t your main priority.
Building Your DECAlink
There are several options for the Corvette owner when ordering a DECAlink. The flexibility of DECAlink allows Corvette owners to use the factory 17-spline differential assembly, or upgrade to a 30-spline differential or Detroit Speed’s hefty Hammerhead 12-bolt differential housing. There are also options for single- or double-adjustable shocks, depending on the end-user’s intended purpose.
We asked Detroit Speed’s Dan Oddy about the need for the Hammerhead differential and when customers should consider the upgrade. “It really depends on the customer’s intention with the build,” Dan said. “If building a 500 to 600 horsepower engine for a Corvette using regular street tires and not seeing any competition, the lower-rated halfshafts and stock differential should do fine. However, if building the same size engine with a sticky tire for the drag strip or autocross events, we recommend stepping up to the Hammerhead differential and upgraded halfshafts. Certainly, if a customer has more than 600 lb-ft of torque, we would recommend the Hammerhead differential and upgraded halfshafts, whether they plan to do spirited street driving or competition.”
The design of the chassis allows for a significant level of adjustment due to the entire suspension being connected through adjustable links between the chassis and the frame. By eliminating the stock leaf spring and going to a full 10-link IRS suspension, you are able to adjust all lateral and trailing links as well as the toe-links to help make a simple change to camber and toe settings for competition mode and street driving. You can also adjust the rear anti-squat geometry and roll-center height with the adjustable mounting positions offered with the DECAlink.
The coilover shock and spring design also make it easy to change spring rates between competition and street driving. By replacing the stock halfshaft axles with modern CV joints and hub bearings, Detroit Speed was able to isolate suspension loads to within the IRS system, and not transmitted through the axle shafts. The outboard, forged, aluminum uprights utilize modern wheel hubs and provide mounting points for the suspension links, anti-roll bar, and coilover shocks. The offset-trailing-link mounting was kept in-board to allow for wider tires and wheels without fender flares — up to a 295 width tire on an 18-inch wheel.
DECAlink’s design will greatly improve the strength of the factory frame with a steel crossmember which attaches in-between the framerails and ties in with the front and rear cross members. This design increases strength and rigidity in the rear of the Corvette to give you the performance driving feel of a late model muscle car.
The First Cut Is The Deepest
As mentioned, the Corvette’s frame needs to be modified to allow the DECAlink to be installed. This includes the original frame bumper brackets, upper shock mount brackets, brake line brackets, and the additional plates used as a doubler at the trailing arm mounts. Later years (most C3s) will need to remove the trailing arm pocket plate from within the top of the T-arm pocket on each side.
While the thought of getting out a grinder to your Corvette’s frame might make some wince, others who are constantly in pursuit of more performance might jump at the chance to cut a considerable amount of time from their laps or E.T.s. That is exactly who Detroit Speed designed its DECAlink suspension for. Detroit Speed has dominated autocross and track days with its 1972 Corvette fitted with the DECAlink system, showing the world vintage good looks can certainly run with the best of them when using modern technology to their advantage.
The DECAlink rear suspension system is equally adept at conquering the open highway as it is at carving corners, which shows the system’s ultimate adjustability and the engineering that went into the design. Let’s take a look at the preparation that takes place before installing the DECAlink chassis and then in the next installment, we’ll highlight the process of putting a great-performing suspension in the back of a C2-C3 Corvette.
We assure you that no Corvettes were harmed in the making of this story. We simply trimmed its toenails so that the new shoes and socks would fit without interference.