Chris Alston first made a name for himself in the ’70s with his door-slammer chassis kits. While they were a big hit, Alston isn’t one to rest on his laurels—today Chris Alston’s Chassisworks offers components for Pro Street, Pro Touring, G-machines, restomods, or any other genre in the hobby you can name. Alston’s product lines include: Chassisworks—components for 1955-2002 GM cars; Total Control—suspension and steering components for 1960-1977 Ford products; Varishock—performance shocks and coilovers; Component Drive Systems—supercharger and accessory drive systems; and KP Components—sport truck suspension systems.
One of Alston’s latest products in the KP Components line is a rear subframe assembly for 1963-1972 Chevrolet shortbed pickups. KP’s frame clip (PN RU4LX-C31) is designed as a suspension update for shortbed pickups, however it can be used to turn a long bed into its more compact counterpart. That’s exactly what we did with Rudy Serna’s C-10.
Installing the KP frame clip begins with removing the bed and stock rear suspension. The framerails are cut at a specified spot and the original rear cab mounts are removed. After cleaning the inside of the ‘rails, the new subframe is slipped in place—it’s properly located when the predrilled holes align with the cab mount holes in the original frame. The new subframe is then bolted in place, followed by a round of welding.
With the subframe secured it’s time to deal with the rear suspension. KP provides axle brackets to mount true four-links (four-links provide adjustment of the attachment points for optimum performance, four-bar attachment points are fixed) with either a Panhard bar or Watts link for lateral control and VariShock coilover or air-spring suspension.
Alston has always been at the forefront of chassis component design and fabrication and his KP line of products continues to prove that’s true. His rear subframe kit is a welcome suspension upgrade for Chevy pickups, and it’s a great way to make a short work of cutting a longbed C10 down to size. Here’s how it goes together.
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Image may be NSFW. Clik here to view.01-02 The after on the left—our C10 is now a shortbed thanks to Chris Alston’s KP Components rear subframe. On the right is what we started with.Image may be NSFW. Clik here to view.03 Removing the bed was the first step in the chassis update. In this case an all-new bed will be installed.Image may be NSFW. Clik here to view.04 Virtually everything behind the cab was removed. Note the shape of the framerails.Image may be NSFW. Clik here to view.05 The truck was placed on jackstands and then leveled. Measurements were taken from the rails to the ground per the instructions.Image may be NSFW. Clik here to view.06 With the trailing arms and the complete rear suspension out of the way the center crossmember was taken out.Image may be NSFW. Clik here to view.07 The framerails were marked for cutting 3/8 inch back from the edge of the cab mount.Image may be NSFW. Clik here to view.08 Call it the point of no return—the rails were severed with a cutoff wheel in an electric grinder.Image may be NSFW. Clik here to view.09 With cab supported and the cuts made the rear section of the frame was removed.Image may be NSFW. Clik here to view.10 After the back portion of the frame was out of the way the rivets holding the rear cab mounts were ground away and the mounts removed. Note the wood block supporting the cab.Image may be NSFW. Clik here to view.11 A wire brush was used to clean the inside of the frame rails, then the flanges were tweaked to make slipping the subframe in place easier.Image may be NSFW. Clik here to view.12 A 7/16-inch drill bit was used to enlarge the cab bracket holes—two more holes per side were added later.Image may be NSFW. Clik here to view.13 Compare the old on the left to the new on the right. The new subframe makes fitting the four-links and larger tires much easier.Image may be NSFW. Clik here to view.14 With a little help from our friends the new subframe was ready to install.Image may be NSFW. Clik here to view.15 The new subframe simply slid inside the original frame—it was supported with another set of jackstands.Image may be NSFW. Clik here to view.16 When the subframe was properly positioned the predrilled holes aligned with the cab mount holes in the frame.Image may be NSFW. Clik here to view.17 With the supplied hardware the new cab mount was bolted in place sandwiching the original rails between it and the subframe (the original cab mounts can be reused, but KP’s are much nicer).Image may be NSFW. Clik here to view.18 After double-checking the measurements taken earlier, the frame and subframe were welded together. Additional holes are drilled and the supplied bolts are installed forward of the cab mounts. In addition holes in the subframe are used to make rosette welds.Image may be NSFW. Clik here to view.19 Finally, stitch welds were made along the flanges of the ‘rails and subframe.Image may be NSFW. Clik here to view.20 In our example the stock rearend was retained, which meant all the original brackets had to be removed.Image may be NSFW. Clik here to view.21 This kit included the four-links, axle brackets, coilover mounts—shown here with the cab mounts and bumpstops.Image may be NSFW. Clik here to view.22 After taking measurements and determining the pinion angle the axle brackets were welded onto the housing. Note the adjustment holes for the four-link.Image may be NSFW. Clik here to view.23 We opted for Chassisworks’ VariShock coilover. The front four-link brackets were already in place on the subframe.Image may be NSFW. Clik here to view.24 The Panhard bar option attaches to the left side of the subframe and a tab on the right four-link bracket.Image may be NSFW. Clik here to view.25 KP Components offers this very clever, bolt-on bracket to mount a Watts link to the stock rearend housing.Image may be NSFW. Clik here to view.26 Here’s the Watts link in place. It keeps the rearend housing centered at all times, which helps handling and can also keep tires from rubbing when clearances are tight.
