BY BRIAN McCORMICK

Anyone who is familiar with customizing a '67-72 GM truck will confess that crafting a frame notch for additional rearend clearance is one of the most difficult tasks you can undertake. Because of the unique frame construction over the rearend, aftermarket manufacturers have shied away from developing an actual notch kit for this particular truck. Unlike the popular late-model trucks, which have a frame that is straight as it crosses over the rearend, the '60-72 truck frame actually bends outward considerably. This has held most kit manufacturers at bay because of the extreme difficulty in designing a marketable notch that is worthy of mass production. 

Consequently, anyone seeking to really lower a '60-72 Chevy truck has had to deal with the axle tubes banging against the frame, or call upon the services of a custom fabrication shop to craft a one-off notch.  Enter the folks at Classic Performance Products, who manufacture one of the largest lines of restoration and conversion products for classic trucks. Since they produce an enormous line of suspension conversion and upgrading kits for '67-72 trucks, it only makes sense they would be the first to tackle the tough job of fabricating a frame notch that actually bolts in. It comes with precise instructions that walk the installer through the appropriate steps for cutting the frame, and describes how to line the notch up using existing frame features. 

The result is a kit that includes a welded frame notch made of 114-inch steel plate, grade-eight mounting hardware, urethane bumpstops and easy-to-follow instructions. Better yet, the process can be done without having to remove the bed. Anyone with a '67-72 Chevy that has been lowered at least four inches definitely needs a frame notch for additional axle tube travel.  Just installing the notch provides an additional three inches of travel, which translates into a greatly improved ride. In addition to the notch kit, Classic Performance Products has also engineered a new adjustable track bar, also called a Panhard bar, to replace the stock non-adjustable version. The reason for this is that when lowered, the stock Panhard bar tends to bind up and pull the rear end to the driver's side as the springs compress. With the new, thicker, adjustable track bar, the precise rear-end location can be set and altered at the owner's discretion.

Here Is the C.P.P. '60-72 Chevy rear frame-notch section that goes above the rearend. Made or 1/4-inch plate steel, this new section is as strong as they come. 

After consulting the instructions. the frame is cut out, as shown.

The C.P.P. frame notch is then pre-fit into the cut-out area to check the fitment. If it fits right, mark the mounting holes with a center punch.

Using a sharp 1/2-inch drill bit, drill out the new mounting holes. 

Classic Perlormance products provides grade-eight hardware to mount the notch. As you can see, this new section fits great and is Incredibly easy to install. You don't even have to remove the truck bed, even though we did for better camera angles. 

While we were at it, the C.P.P. staff decided to show us their new adlustable track bar. After removing your old Panhard bar, simply insert one of the ends into the rearend stud.

The end that attaches to the frame is the adjustable end.Turn the end until you have the appropriate length, then install and tighten the jamb nut. 

With that, you now have a better rear suspension. The thicker, adjustable Panhard bar will definitely come in handy, and can be adjusted without having to raise the truck.