Fatman Fab Rear Suspension Kit - Versatile Four-bar

With the step notch installed, we’ve gained nearly 8 inches of travel; more than enough to lay the truck out flat in the weeds and still have plenty of clearance for the rearend. Also note that the stock crossmember has been removed.

The rear suspension components are back in place and now it’s time to setup the ride height. We’re going to setup the rearend at 15 inches from the ground to the center of the axle to simulate a 30-inch-tall tire.

With the side and top plates of both step notches welded up, the stock framerail can be cut out, thereby creating the step notch. Welding up the step notch first and then cutting out the center section as opposed to cutting the frame first eliminates the possibility of tweaking the frame.

We adjusted the height of the chassis on the lift to get our proper ride height. Fatman calls for the crossmember to be even with the axle centerline so it will be necessary to move it up into the frame about three inches.

A Sawzall makes quick work of removing the offending area.

The crossmember is now tacked up into the framerail and the four-bar brackets can now be tacked in place. They’re set in place 2 inches from the center of the bracket to the framerail.

The rear axle brackets can now be tacked to the rearend. We had Currie slide them onto the axle housings before they welded up the axle flanges so we didn’t have to split them. The rearend was setup with 6-degrees pinion up with each four-bar measuring 23 inches, center to center.

We’re using Ride Tech coilover shocks on all four corners on the ’75 and the Fatman kit requires the upper mounts be welded to the outside of the framerails. The shock does a pretty good job of holding the tabs in place, but Fatman says to locate them 5 1/2 inches behind axle centerline, roughly 12 to 12 1/2 inches above the mounting hole on the axle bracket. Here’s a hint: splitting the difference between the four possible mounting locations will give you a bit of ride height adjustment.

The Z-bar bracket mounts off the passenger-side, rear lower four-bar bolt and connects to the driver-side front lower four-bar bolt. Both brackets and rod-ends are attached…

…before the bar is marked and cut to length.

The threaded bungs provided in the kit are then welded to each end, completing the Z-bar assembly.

To stiffen up the chassis, we decided to box the framerail from the step notch forward to the next crossmember.

It’s also possible now to finish off the ends of the crossmember by cutting off the unnecessary bit and capping the open end off.

A crossmember added between the rear kickup of the step notch helps stiffen up the area where the shocks mount.

The disc brakes we’re using out back are Wilwood 13-inch drilled and slotted discs with four piston calipers. First, the caliper bracket is bolted to the axle flange using the provided spacer and hardware…

…followed by the rotor and caliper.

Wilwood’s method of installing brake pads is ingenious and makes swapping out pads a snap. Simply remove the center fastener and spacer above the brake pads and slide ’em out.

It should be pointed out that the Wilwood hat and rotor need to be assembled prior to installation; this means properly securing the fasteners via safety wire.

And there you have it! A four-link setup that will handle as good as it looks and get the C10 way down deep in the weeds.