Modifications to your '68-'82 (C3) Corvette's suspension can be quite rewarding. Simple attention to and maintenance of a stock 22-plus-year-old suspension will greatly improve the car's handling and ride quality. Add a few technologically advanced suspension tweaks and you can reinvent your Corvette altogether.
We decided to freshen up our '68 convertible's front end with Speed Direct's new Shark Bite coilover spring and shock packages for '63-'82 Corvettes. Each Shark Bite kit includes a pair of rebuildable Afco shocks, two QA1 springs, mounting adapters, and all the hardware to replace your stock front springs and shocks with modern technology. The single-adjustable shocks allow you to adjust rebound, while the double-adjustable units allow for setting both rebound and compression parameters.
The kits cover all the possibilities, with non-, single-, and double-adjustable shocks available, and your choice of two different spring rates. The small-block springs have a progressive rate of 250-350 in-lb, and the big-block units have a rate of 350-450 in-lb. Both springs are interchangeable, so small-block owners can opt to use the big-block packages for a stiffer ride and vice versa. The company says even higher spring rates will be available soon.
We opted for a double-adjustable small-block kit for our '68 L79 Corvette. The installation was straightforward. We started by jacking up the front of the car and placing it firmly on jackstands, then removed the nuts on top of the stock shock absorbers. We disconnected the end links from the front antisway bar and swung it out of the way. Next we removed the two bolts holding the bottom of the shocks and dropped them out of the car. We unbolted the front brake calipers and hung them out of the way with sturdy wire to avoid damaging the flexible, rubber brake lines.
Use caution when removing the front coil springs. They're under a tremendous amount of tension, even with the weight of the car off the suspension. Rent or acquire a good spring compressor, install it on the springs, and cinch it up securely before splitting the spindle from the upper ball joint with a pickle fork. If you don't know what you're doing, stop and enlist the help of a professional.
If you overlook the spring compressor, the spring could jump out of its pocket and ricochet around your garage with a surprising amount of force when you let down the lower A-arm, potentially creating a dangerous situation.
A floor jack is moved into position under the lower A-arm to help keep the spring in place while letting down the suspension. Remove the cotter pin from the castle nut holding the spindle to the upper A-arm and remove the nut. Use a pickle fork and a hammer to separate the spindle from the upper ball joint. The suspension is lowered with the floor jack.
Prepping the Shark Bite coilovers for installation is a matter of assembly. First, the large spring adjustment nut is threaded onto the shock-absorber body, making sure the tapered part of the nut is oriented toward the top of the shock. Install the crossbars through the lower bearing on the shocks and secure them in place with the supplied snap rings. Grease the Timken bearings and sandwich them between a pair of large washers before slipping them onto the spring adjustment nut.
Installation is basically the reversal of removal. Remove the nut, washer, and bushing from the top of the shock and make sure the shock is fully extended. Place the new coilover spring on the shock. The new shocks rest on top of the lower A-arm; in the stock configuration, they are bolted from the bottom. Bolt the lower part of the shock onto the A-arm, torque the bolts to 20 lb-ft, and guide the top of the shock and spring into the pocket as you raise the jack.
The spring end on top of the new spring must fit into the indentation in the spring pocket. With a marker, draw a line down the coils of the spring to mark the spring end, and put a similar mark on the bottom of the spring pocket to show how the indentation is oriented.
The floor jack is positioned under the lower A-arm and the suspension is slowly raised into position. A quick check of the alignment marks, once the assembly is near the top, ensures the spring ends are properly oriented into their indentations. Guide the shock stud into its hole from the top side and continue to lift, also making sure the spindle mates properly with the upper A-arm.
The castle nut and cotter pin holding the spindle to the upper A-arm are replaced, and the new bushing, washer, and nut are screwed onto the shock stud finger-tight. The final torque of 8 lb-ft is applied only after the car is back on the ground.
Adjusting the shocks and the car's handling characteristics on our double-adjustable shocks is accomplished at three points. The first, rebound valving, is set using a small, long, flat-blade screwdriver inserted into the top of the shock stud. Turn the adjuster clockwise in quarter-turn increments for stiffer valving, using eighth-turn increments for fine tuning. Compression is adjusted with the knob on the bottom of the shock. It's set at 5 from the factory; 1 is the softest setting and 8 is the stiffest.
The car's corner weight is adjusted using a special spanner wrench (available from Speed Direct) on the adjustment nut at the bottom of the shock. Turn it clockwise to increase the corner weight and counterclockwise to reduce it.