Complete Guide to Cowl Steering Box Conversion for Hot Rods
Steering Box Options for Hot Rods | Why Choose a Cowl Steering Conversion Kit
There’s just nothing quite like dragging home a 100-year-old car or truck body and then meticulously crafting all the pieces needed to make it into a running, steering, and stopping hot rod. Since many of these projects start with little more than that ragged old body, it then falls to the builder to create all the systems necessary to get it out on the road. The steering system is often a big question mark. With so many options for various steering boxes and locations, it can be tough to figure out the best of all the rat rod steering ideas to determine the best hot rod steering setup that will be effective, safe, and actually fit into the tight confines of a hot rod chassis. A century or so of hot rodding has produced a few favorite setups, each with advantages and drawbacks. We will be discussing all of them here, with extra emphasis on the oft overlooked cowl steering setup. This “outside the box” setup may be just the ticket for your traditional hot rod, and Speedway Motors has a product solution designed to streamline the process of fitting one to your car.
Cowl steering can be defined as a hot rod steering system where the steering box is inside the cowl portion of the car’s body (thus the name) instead of outside the body mounted to a frame rail or crossmember. Hot rods using this setup are easy to spot because most typically the pitman arm protrudes from the side of the cowl.
Even a cursory look back through racing history shows that cowl steering was the standard setup for early open wheel race cars, and in fact a much-modernized version remains in use on contemporary sprint cars. But it’s less common to see a cowl steering setup on road-going hot rods. Instead, most traditional rods use some version of a frame-mounted box in either a “traditional” setup, as was standard on early Ford’s until 1935, or the “cross-steer” setup that followed on all fat-fender Fords.
While you hot rod historians out there will likely be able to come up with other examples, the first well-publicized use of cowl steering on a hot rod was Doane Spencer’s famous black Deuce roadster. Early versions of the car used more typical steering setups, but in the process of preparing the car for the gnarly (and ultimately cancelled) La Carrera Panamericana Mexican road race, Spencer fit the car with a racy Schroeder steering box and a pitman arm that protruded from the cowl side. Fast forward a few decades and a couple guys in New York calling themselves the Rolling Bones took some of Spencer’s groundbreaking ideas (including that Shroeder steering setup) and applied them to a string of wicked hot rods that garnered much attention from the automotive media. These cars likely did more than anything else to expose traditional hot rod builders everywhere to the idea of cowl steering.
Cowl Steering Setup Diagram: Hot Rod Steering Explained
Those builders and the old open wheel racers that preceded them understood the advantages of a hot rod cowl steering setup when compared to the more common types of steering linkage. First, if you’ve spent much time behind the wheel of a hot rod, you know that space in the footwell is at a premium. Add a clutch pedal or a channeled body and the situation is even worse. On cars using a typical hot rod steering box like an early Ford, F1, or street rod steering box like a reversed Corvair, the steering column passes right through the footwell and compounds the problem. Not to mention header clearance issues where the box bolts to the frame rail. With a cowl steering setup, the box is positioned higher up in the cowl, freeing up much needed space for your feet and your exhaust.
Another ergonomic benefit of cowl steering is a more favorable steering wheel angle. Early cars with the box on the frame tend to have a severe upward angle on the steering column. This can lead to the uncomfortable feeling that you’re driving a school bus. With the steering box positioned higher in the cowl, that steering angle is less severe and more like a contemporary car.
Another advantage that a cowl steer setup can create is more favorable bump steer geometry. On a straight axle car with traditional steering, bump steer occurs when the drag link travels in a different arc than the steering arm that’s bolted to the spindle. To greatly simplify the relatively complex concepts that pertain to steering geometry and Ackermann angle, consider that the end of the radius rods or wishbones is the axis about which the axle rotates as it travels up and down. It stands to reason then that a near ideal situation would be created when the drag link is positioned at roughly the same angle and with the pivot point as close as possible to that of the radius rods. Look at a traditional car with the drag link angle all akimbo as it points sharply upward from the pitman arm and you can see the problem. Cowl steering makes it easier to dial in more reasonable geometry.
Cross-steering setups like those originally found on fat-fender Fords and more modern versions using a Vega box are another way to create much better bump steer geometry. The issue with these setups is that you have to connect the steering column to the box clear out in front of the car. Some DD shaft and a couple u-joints will usually do the job, but it’s always tricky to route the shaft around the engine and headers. An offset steering box can be handy in this situation, but the modern components can look out of place on a traditional hot rod or rat rod steering setup.
And finally, we can’t overlook the fact that cowl steering just looks cool. That pitman arm hanging out the side of the body functions a bit like a blower through the hood, adding a function over form, racecar aesthetic element that’s just plain killer on the right car.
Building a Cowl Steering System: What You Need
If we’ve sold you on a cowl steering setup for your hot rod, you may be wondering what it takes to make it all happen. There are several ways to do this. One option is to scrounge to source an old Schroeder box. These are no longer in production and are pricey if you can turn one up. While it’s hard to beat the cool, finned look of the racecar-derived steering box hanging out under the dash, there are drawbacks to these beyond the unobtanium factor. If you do find one and can source the Schroeder steering box parts needed to make it work, it’s likely that the gear ratio of the box is too quick for a street car. Remember, these were meant for circle track racing, where small corrections to the wheel keep the car off the wall and away from other racers. Put a quick ratio like this in a street car and it can be annoying and unsafe.
Throughout history, builders have modified commonly available hot rod steering box options like the F1 pickup box to work with cowl steering, with mixed results. Take a look around the internet at “rat rod steering box” options and you’ll see some attempts that are sketchy at best. In recent years, clever hot rodders have figured out another cowl steering box option. The steering box found in a whole slew of 60’s and 70’s Mopar cars is uniquely suited to hot rod cross steering. While at first this may seem like an odd choice, a closer look reveals some unique benefits. First, the housing is made of cast aluminum, and with the right treatment can offer some of the racy, hot rod-perfect looks of the old Schroeder box. Cast into that case are some stout mounting points that lend themselves well to being bolted to a fabricated plate and attached to a support structure. No reversing or other internal mods are necessary, and the leg of the box where the pitman arm attaches is offset relatively far to the left of the steering column input, placing it closer to the cowl side.
Like everything else in hot rod building, the Mopar box still requires significant fabrication to adapt it to a hot rod or rat rod cowl steering setup. There are two main areas that need to be figured out by the builder. First, the box needs to be attached to something stout. Frame mounted boxes are easy, but cowl steering boxes cannot just be bolted to the body. There’s just not enough structure in an early car body to handle the extreme forces that will be applied to a steering box. As such, most builders who have successfully adapted a Mopar box for hot rod cowl steering have made a tubular structure that bolts to the frame and supports the steering box. This requires some fabrication chops, but can be accomplished by just about any resourceful builder with a cutoff wheel, some tubing, and a good welder.
The second issue is the attachment of the pitman arm. Though it’s closer to the cowl side than other options, the point at which the pitman arm attaches will still be inside all but the tiniest of hot rod cowls. For a typical Model A cowl steering setup, an additional eight to ten inches is usually required to get the pitman arm outside the cowl with adequate clearance. Also, the pitman arm itself will need to be sourced and adapted or fabricated. Builders who have done this in the past have spent significant time standing at the lathe and bandsaw while scratching their heads trying to create the right tube, bushings, brackets, and pitman arm for their car. Anyone without access to the right tools and a good TIG welder will have extreme difficulty here. This is where the Speedway Motors Hot Rod Cowl Steering Conversion Kit is a life saver. This kit comes with all the right stuff to complete this step, right out of the box, including the bracket to mount the box, tube with the splined end welded in, support bushings, and the pitman arm itself, making this job much easier for anyone and bringing it within reach of most home builders.
Step-by-Step Guide to Installing a Cowl Steering Box in Your Hot Rod
The steps for adapting a cowl steering kit to your hot rod are going to vary significantly depending on the type of car and builder preference. Here are some rough guidelines to consider as you plan your approach.
Step 1: Determine seating position. This may seem unrelated to our steering project, but this is the first step to creating a hot rod that is comfortable to spend time in. Mock up the car as completely as possible and place the driver’s seat where it’s going to go. Then, you can use a steering wheel and something to represent a steering shaft (wooden dowel works well) to determine a comfortable location for the wheel. This will tell you the height and side to side location of the box as well as the angle. Take your time on this step.
Step 2: Use something like jack stands or a stack of wood to support the steering box in the location that you have determined. Look around at the rest of the car to assess the big picture. Does the placement of the box make sense relative to the cowl and dash? Will the pitman arm protrude through the cowl in a functional and aesthetically pleasing location? If using the Speedway Motors Cowl Steering Fab Kit, does the tube position the pitman arm clear of the cowl and any hinges or other obstacles it will encounter as it rotates? Is there clearance behind the dash for gauges? Is there a logical way to add a steering column and support with room around the wheel for your hands to move freely? If any of these considerations cause you to move the box, repeat your steering wheel mockup from step one.
Step 3: Once the box is positioned where you want, it’s time to plan your mounting framework. A word of caution here; there are significant forces on the steering box. Don’t just plan for the regular force of the steering input acting on the steering arm. Instead, consider the dramatic spike in the forces being applied to this assembly when the front wheels hit something like a curb or a pothole. This force is compounded by the fact that the framework that you are building will cause the box to be “cantilevered” above the frame by a foot or two. “Good enough” is not good enough here. This needs to be a very stout assembly, so plan accordingly. Round or square tubing works well, and the Speedway Motors kit comes with a cut and bent bracket to facilitate mounting the box to your structure. Bolting the framework to the car’s chassis will add some flexibility when compared to welding, but once again build it stout and use high quality fasteners that are in double shear and are large enough to handle the force. Also consider the opportunity to brace the car’s cowl to the framework for added strength and support.
Step 4: The Speedway Motors kit comes with a pair of neat bushed support collars with spherical bearings to allow for the angle of the bracketry and cowl side. The tube that attaches to the box and extends out the cowl side is 9” long and needs to be supported as far out as possible. The inner support bushing is designed to attach to a stout inner support to provide stability to the tube extension. Consider using a piece of 10-gauge or thicker plate attached to the box support framework. The second bushing serves as a way to cleanly finish the spot in the cowl where the arm passes through. Locate this hole carefully and drill or cut the cowl side.
Step 5: It’s time to attach the steering wheel and column. The steering column cowl steering works best with will largely be determined by your car and configuration, but the Mopar boxes use a 5/8”-36-spline input, so commonly available adapters and U-joints will work to adapt whatever hot rod steering columns you choose. If you were careful with your mockup from step one, there should be a logical path for the steering column, column drop, and steering wheel to fall.
Step 6: With the box assembly all mocked up, you can measure for the drag link that will attach to the steering arm on the spindle. Be sure the car is at ride height and the wheels are centered. Speedway Motors tie rod and drag link kits are ordered with the assambled, center to center dimensions, not the tube length.
Essential Parts List for Your Cowl Steering Conversion
Here’s a quick rundown of the parts you’ll need before you get started on your Mopar cowl steering project.
Speedway Motors Hot Rod Cowl Steering Conversion Kit for Mopar Steering Box
Some steel tubing and/or plate to build a frame to support the steering box. You’ll also likely want access to a welder and some cutting tools.
Steering column or steering shaft and a column drop or support bearing.
5/8-36 Spline Adapter or U-joint between the steering column and the box.
Steering linkage. The pitman arm in the Speedway Motors kit is drilled with a tapered hole for an early Ford 11/16 tie rod end, so a Speedway Motors Tie Rod/Drag Link Kit will work well for the drag link that connects to the steering arm on the spindle.
Now that you have the steering sorted out, check out all the cool hot rod parts from Speedway Motors to transform that crusty old body into the cool hot rod that you sketched on your notebooks in study hall.
