The spindle will need to be slightly clearanced to clear the lower shock once at ride height. Grind around 5/8″ up from the bottom of the spindle.

See the mark on the spindle for the area to clearance. Only need to take about 1/6″ of material.

Install the shock inserts, then the 1/2″ lower onto the lower plate and torque to 60 ft/lbs. This will not be accessible once installed on the lower control arm.

You can install the sway bar end links now for ease of installing the lower bolt, or install after mounting the lower plate to the lower control arm. We installed the end links before mounting the plate.

To install the shock, the upper portion must go in first. Hold the spindle away from the frame to gain enough clearance for the shock clear the control arm and the lip on the frame.

The upper clevis is offset for spring clearance. Ensure that the offset is pushing the eyelet of the shock towards the outboard (wheel) side of the car.

To install the lower mount, by pressing down on the lower control arm while holding the spindle away from the frame. Install the top two retaining bolts as the one next to the end link is very tight.

Next, lift up on the control arm to reinstall the lower ball joint and tighten the lower mount bolts. Tighten the two top mount bolts, and torque to 35 ft/lbs followed by the one on the side by the sway bar mount. The fourth hole is optional but recommended for additional strength.

Tighten the upper clevis next. You’ll need a 10mm wrench to keep the clevis in place. The eccentric washer will need to have the thin side towards the outside of the car to maximize spring to frame clearance. Torque the M14 nut to 50 ft/lbs.

These bolts all take a 13mm socket or wrench.

Completed unit, ready for ride height adjustment.

Before installing the upper sway bar end link, you’ll want to set final ride height. Loosen the jam nut and spring collar to desired height. The shocks ship with the spring only hand tightened so the spring doesn’t rattle during shipping. This should be near factory ride height though.

The car will need to be rolled or driven a very short distance to get the suspension to settle. Typically 100-200 ft should be plenty. Adjust ride height as needed and settle the suspension each time.

After driving on a four post lift or up on ramps, install the upper sway bar end link. The suspension will need to have the full weight of the car to properly adjust the end links. Position the sway bar at the desired height and adjust the end links accordingly. Tighten down, align the car and you’ll be ready for a new riding and/or handling early model C4 Corvette.

Remove the carrier bearings, ring gear, plates and springs, then clutches.

Chuck the posi in a lathe and ensure it’s centered. Dial indicator is to make sure the unit is running true on the lathe before machining.

Standard ID on the posi is around 1.247″.

This will need to be opened up to a diameter of 1.295″ for the new axles with a step cut coming next.

Your posi should now have a bore of 1.295″ and a step that is 1.395″ on the outer edge of the bore that is .325″ deep. This allows the new side yokes to be pushed in far enough to install the 12 bolt c-clips during assembly of the differential.

Finally, sand or file the hard edges and clean the posi before re-assembling.