New Speedtech Chassis Takes First-Gen F-Body To The ExtReme

World-renowned physicists have long toiled over the theory of transferring matter instantly from one point to another. The popular TV series “Star Trek” made the concept a household name, routinely teleporting teams of people between spaceships and planets. Once only considered in science fiction circles, the folks at Speedtech Performance have more recently shown us how it might be done with a vintage Camaro and its new F-body chassis upgrade.

We’re not suggesting that the completely new Speedtech Performance ExtReme chassis will warp the laws of physics, but it will push the car’s capabilities to the very boundaries of those laws. With a Speedtech Independent Rear Suspension (IRS) at its core, the new F-body chassis upgrade is a total revamp of what was once considered quick, and literally, rebuilds speed from the ground up.

Speedtech ExtReme chassis Camaro

The new Speedtech ExtReme chassis is not a bolt-in upgrade. But when you’re changing the DNA of your ride, you need to make some deep cuts. How many first-gen project cars need a replacement floor anyway?

Building A Solid F-body Chassis

When it comes to building a solid, performance chassis, rigidity is key. This new ExtReme IRS F-body chassis upgrade was designed with that goal at its foundation. The new frame rails feature box-welded construction with tabbed-through-frame gussets for added torsional rigidity. The rails span from the rear of the body, all the way to the firewall, and are continually braced throughout the underside of the vehicle. Then, the entire chassis and floorpan are engineered to weld together, tying them directly to the car’s inner rocker panels. This provides the ultimate rigidity to mount Speedtech’s ExtReme front subframe and ties the entire vehicle’s body into a much more solid uni-body construction than the OEM design.

The team at Speedtech has been using their expertise in engineering to optimize the potential of this new F-body chassis upgrade. With careful calculations and modern 3D scanning, the team at Speedtech has been able to build an even more solid foundation that allows GM’s first-generation F-body to hit unprecedented goals with the new chassis.

Computer-Aided Design (Left) has infiltrated every aspect of hot rodding and Speedtech used this new technology to create its new ExtReme chassis for F-bodies (Right).

Enthusiasts can now stuff a massive 355 mm tire in the rear with no outside fender modifications and a 315 mm-wide tire up front with over 30 degrees of steering angle. The suspension has been corrected for better Ackerman, allowing up to 20 percent more grip on the inside tire during cornering. While going straight, this new chassis enjoys virtually zero bump steer (only .005-inch over the entire suspension travel) so the two wheels out front are in constant agreement with the one in the driver’s hands.

what is Ackermann in a front suspension?

Randy Johnson’s Speedtech-equipped 1969 Camaro shows how proper Ackermann affects the steering angle difference between inner and outer tires during a turn.

F-body Chassis Upgrade With Options

As you can imagine, this ExtReme chassis is designed to upgrade the entire suspension of a first-gen Camaro or Firebird, with a multitude of available options. Starting in the back, performance junkies can choose either a low-mounted (Corvette-style) or high-mounted cantilevered shock assembly. Thanks to the modular design of the new chassis, customers who already have a Speedtech Pro Touring or ExtReme front subframe can retrofit it to the rest of the suspension for a completely independent suspension front and rear.

The front subframe (Left) attaches to the new frame rails fitted to the body. You can see the additional gusseting (Center) working its way to the rear suspension, which can either be a Corvette-style (lower) or a jewel-like, cantilevered (high) rear shock design (Right).

A set of custom-valved QA1 shocks is available with the spring rate of your choosing, along with splined, three-piece Chromoly, tubular sway bars, which are three-position adjustable for on-car fine-tuning.

The chassis accommodates a variety of drivetrain options, including LS, LT, small-block, and big-block Chevy engines. The fully adjustable transmission crossmember allows the fitment of just about all conceivable engine and transmission combinations. Note that oil pan compatibility is chassis-specific and the pan used must fit around the steering rack.

ExtReme Front Suspension

The ExtReme chassis front module features Speedtech’s forged spindles with maintenance-free sealed bearings. These spindles are formed from lightweight 7075 aerospace aluminum and feature optimized geometry over the standard Corvette-style spindle. The suspension’s improved geometry requires less caster to achieve an optimum tire contact patch while turning.

You get the largest steering angle and proper Ackermann steering geometry dialed in; so both tires are turning on a common center point, giving you more contact with the street. – Cameron Foremaster, Speedtech

There is also a Sweet Manufacturing rack and pinion steering gear for precise control of each front wheel. While the length of the OEM steering column will not work with the ExtReme F-body chassis, Speedtech has designed the system to work with an ididit column, which can be specified at the time of order.

Speedtech ExtReme first-gen F-body chassis installation

This installation uses the cantilevered rear suspension. Even with all the modifications, Speedtech reports that the stock interior fits, including the rear seat and console.

ExtReme Independent Rear Suspension

When you choose the cantilevered IRS option, you’ll have a set of billet aluminum, high-mounted rocker arms articulating with your rear suspension’s travel. The rear suspension is adjustable for ride height, caster, camber, toe, spring rate, and rebound, to provide you with a great ride, all-out performance, or anything in between. All ExtReme IRS suspensions come with a Dutchman aluminum differential housing fitted with your choice of gear. On each side, you’ll find axles rated to 1,200 horsepower with optional 1,800 horsepower-rated half-shafts available.

Speedtech IRS

Speedtech’s jewel-like ExtReme independent rear suspension is where things get interesting. The IRS assembly comes as a removable subframe but can be welded in for the ultimate rigidity.

Going Beyond The ExtReme

As if this entire upgrade wasn’t enough, you can also go even further, beyond “just” the extreme, and specify components to help your build go more smoothly. Speedtech offers adapter plates to help mount a variety of engines, as well as the appropriate urethane mounts to hold everything in place. To further help you get your chosen engine up and running, Speedtech offers several stainless-steel 1-7/8-inch header designs to cover most applications.

Both front and rear ExtReme suspensions are available with either Baer or Wilwood brake upgrades and an “e-brake” is optional. There can be a frame-mounted battery box added to the chassis, as well as cooling options for up front and a fuel tank in the rear. Of course, by setting up the chassis, Speedtech knows what wheels and tires fit best and can advise you on the best option for your application.

The Speedtech floor pan (Left), firewall, and transmission tunnel (Center) are installed in sections, tying everything together as they are welded in place (Right).

The new Speedtech Performance ExtReme chassis for 1967-’69 Camaros or Firebirds is clearly aimed toward those g-thirsty enthusiasts looking to push the envelope further than ever before. We can’t specifically say that installing the new Speedtech Performance ExtReme chassis into your 1967-’69 Camaro or Firebird will help you teleport your way around town or the autocross. But, once you get that front and rear IRS dialed in, changing direction will almost feel instantaneous, and you’ll have a much better working relationship with the laws of physics as well.

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About the author

Andy Bolig

Andy has been intrigued by mechanical things all of his life and enjoys tinkering with cars of all makes and ages. Finding value in style points, he can appreciate cars of all power and performance levels. Andy is an avid railfan and gets his “high” by flying radio-controlled model airplanes when time permits. He keeps his feet firmly grounded by working on his two street rods and his supercharged C4 Corvette. Whether planes, trains, motorcycles, or automobiles, Andy has immersed himself in a world driven by internal combustion.
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