Classic Performance Products Trailing Arm Conversion Kit - Leaves Are For Trees

Jeff got comfy with the drill for a while and transferred all the holes in the reinforcement plates to the frame, then tightened down all its bolts, except for the three on each side that hold the shock crossmember in place.

Next, cut the stock leaf spring pads and shock mounts off the rearend housing and ground the remnants smooth. Remember to wear your safety attire!

Now CPP's tubular trailing arms can be hung from the trailing arm crossmember. CPP has recently revised their tubular trailing arms by adding longer reinforcement plates and doubling the tubing wall thickness from 1/8-1/4-inch-wall DOM tubing. This came about when a customer installed them in a turbo diesel-powered truck with 1,400 lb-ft of torque and was starting to bend the old ones, so even if you have an older set, they'll probably stand up to more power than most will ever dream of having.

With the rearend housing tubes ground smooth and cleaned up, it was hoisted back up in place where the new U-bolts and trailing arm pads were installed. Just snug the U-bolts down for now.

The new coil springs were installed with all the provided hardware. CPP has six different heights of coil springs and three lowering blocks to give plenty of ride height options. The '79 got the 3-inch drop springs and no lowering blocks for now.

With the U-bolts still barely snug, Jeff carefully checks to make sure the rearend is centered in the truck from side to side.

With the rearend centered and set at ride height, the pinion angle can now be set. The motor's crankshaft centerline was checked at the transmission's tailshaft and was determined to be -6.2 degrees, so the pinion angle was set at the same degree reading but slopping up or positive. Now the U-bolts can be tightened down.

Double-check the pinion angle and make sure the rearend is still centered before tack welding the trailing arm pads to the rearend.

CPP includes one of their adjustable Trac Bars and mounting brackets in the kit. With the rearend still sitting at ride height, Jeff test-fits the Trac Bar before welding its mounting bracket to the rearend.