Second Gen Truck Arm Paradox

Once we’d made the decision to go the NASCAR route and use truck trailing arms in the rear, it was time to gather up the required pieces. This started with the arms themselves and associated crossmember from Carl’s Racing Products. Once we received everything, the scope of this task became a little clearer.

Pressing into the Unknown

After much spirited debate, and some more investigating, coilovers mounted directly off the back of the trailing arms seemed to be the only possible solution that didn’t involve hacking the entire back of the car up. Competition Engineering again came to the rescue with the lower coilover mounts, which we attached to custom plates which were bolted, then welded, to the trailing arms.

The only installs we could find online were on first gen Camaros and multiple years of Novas and Chevelles, most using the kit from Hot Rods to Hell. Problem no. 1 is in locating the springs: all of the vehicles we could find pictures of happen to have a substantial amount of room in front of the axle, which is where the coil springs typically go. On a second gen, however, there’s simply no room for them without cutting out the floor in the back seat area.

The other issue was the floor. One of the improvements of the second generation F-body cars was increased legroom – or maybe headroom – afforded by deep wells under the seats. Deep wells are great for headroom, but not for accommodating long metal bars extending toward the transmission.

Again the plasma, MIG, and some scrap steel made relatively quick work of the issues, albeit over several sessions. What was that he’d told us about not wanting to let someone just ‘cut it up’?

Panhard Bar

The next item on the agenda was preventing side to side motion. Like any link suspension build, this again presented many options – namely a traditional panhard rod, or a more complicated (and heavy) watts link.

Keeping with our “keep it (relatively) simple” approach, the panhard rod that the General saw fit to put on the trucks won out. There are inherent flaws with this design (outlined by Jason Rhoades more succinctly than I could ever hope to do here), but these are minimized in a setup with limited travel.

A sliding mounting point on the frame would provide the needed adjustability, and after several hours on the Bridgeport and TIG table we had all the pieces together.

Fitting it all Together

Packaging everything into the rear required more permutations than we care to remember. In the end, the solution was addition by subtraction – one 2″ square tube crossmember for the shock and panhard bar mount. By mounting the shocks off the rear of the bar, and the panhard bar mounting tube off the front, we gained just enough clearance for everything to mesh together. This condensed packaging paid off later, as the room in front of the axle proved ample for a Competition Engineering rear anti-roll bar kit.

With that, it was on to the front, with a prerequisite that it would not take the better part of a year and a half to complete as the rear did.

More Process Pictures