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Manufacture Spotlight | The Roadster Shop’s Chassis for Late-Models

ST-STAFF . June 16, 2020 . F100 Builders
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CUSTOMIZING F-100S has been a popular trend for many decades, but the most coveted generation was the 1953-56 model. These days there has been a growing interest in the “later models.” Specifically, the 1967-72 bump-side F-100s have been gaining traction with custom versions sprouting up at shows throughout the country, and The Roadster Shop team is keeping up with the trend.

Although The Roadster Shop has offered options for classic trucks for a while, the price tag was a bit steep for most builders. A few years ago, the company used new technology to develop chassis for those on a more moderate budget. By creating a frame that would take less time and labor to form, the Spec Series chassis comes at a lower price point out the door. These chassis have been a big hit with other truck models and now the same components are available to help the up-and-coming bump-side F-100 pickups.

A while back, The Roadster Shop team saw an increased interest in parts for 1967-72 bump-side F-100s. After making the decision to create the entry-level Spec Series chassis, the team 3D-scanned a guinea pig to serve as a base so that they could build a computer-simulated chassis that would provide these trucks a 4-inch ride height.

Getting things rolling, the Roadster Shop 3D scanned one of these trucks and uploaded the data to a computer. From there, the team was able to develop a frame and chassis to make it go low on Strange Engineering coil-overs or lay the body on the ground with airbags. After the computer-modeled chassis was created, it was tested with a special suspension program to simulate how it would react under real driving conditions. Once they were happy with the design, the team pressed the “print” button and a real version was printed in 3D and ready for assembly. Afterwards, it was installed and driven on the streets to get real-world feedback on performance, and it did its job just as expected.

The chassis was designed to come together in less time, but also to perform on a track. To make this possible, the frame is formed by making specific cuts, bending it together and welding it solid. The front suspension consists of fabricated lower control arms and tubular upper control arms with eccentric  mounts for easy alignment. Specialized Wilwood forged spindles are combined with rack-and-pinion steering to minimize effort during turning. The rear suspension is comprised of a triangulated 4-link with a 9-inch rearend. The frame is also equipped with all of the correct mounts so that the body can be bolted directly to it.

For all of these reasons and more, the Spec Series chassis is revolutionary. If you are planning to build a 1967-72 F-100 from the ground up, there is no reason to start your project with a tired old frame with obsolete components. This is especially true for a build that will showcase a high-performance engine and will be expected to hold down that power. Some of the optional components in pricing on these chassis are AFCO dual-adjustable coil-overs, 11-14-inch disc brakes, a front sway bar and rear end gearing. The chassis’ list of the advantages goes on. Continue reading to check them out yourself.

The front suspension on this chassis is comprised of fabricated lower control arms and tubular uppers with eccentric mounts. Between the arms are forged spindles and AFCO dual-adjustable coil-overs (Strange Engineering single adjustable coil-overs are standard) for the nonairbagged version.
Modern turning capabilities come from the power rack-and-pinion, while body roll can be minimized with the optional sway bar.
Here’s a computer model of the ’bagged version of the chassis. As you can see, ’bags replace the coil-overs here and monotube shocks are externally mounted.
The transmission cross member can adjust to different locations and will drop out for maintenance. The rear cross member is notched for the driveshaft and exhaust.
Various motor mounts are available and include versions for Coyote, SBF, SBC, BBC and LS engines. Though the chassis does have options for these drivelines, the transmission tunnel will need to be modifi ed, which is unavoidable to make these trucks go super low.
The rear suspension uses a triangulated 4-link to hold the 9-inch rearend with 31-spline axles in place. The rear frame kickup allows the axle to travel upwards so that the truck can lay body on the ground. The chassis was engineered for minimal bed modifications and to fi t up to 12-inch-wide wheels (345 tire width) with the use of mini-tubs.
The rear on the coil-over version is very similar to the ’bagged version. The coil-overs are mounted outside of the frame for better function while the truck is turning.
This top view gives you a good idea of how simple yet well engineered the chassis is. There are just enough components to get the job done at a more moderate price.
With the suspension fully compressed, the chassis will allow for the body of your bump-side F-100 to kiss the pavement with a maximum of 29-inch-tall tires.
Starting at under $10K, the Spec Series complete chassis are a bargain. Though this may sound like a big chunk of change, it is money well spent and will completely modernize the way your classic truck rides and handles. You can piece together other systems, but you may end up spending more in the long run without benefitting from a complete chassis. If you are starting a ground-up build on one of these trucks, you will want to consider the Spec Series.
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