C-Notch Kits for Lowered Trucks, Hot Rods & Custom Vehicles

Gain Rear Axle Clearance Without Sacrificing Your Stance

When lowering a classic truck, hot rod or custom vehicle, rear axle clearance quickly becomes one of the biggest limitations to usable suspension travel. A C-notch modifies the frame rail above the rear axle, creating additional clearance so the suspension can compress without the axle housing contacting the frame.

Scott’s Hotrods C-Notch Kits are designed for builders who want an aggressive lowered stance while maintaining the suspension travel necessary for a vehicle that actually drives properly. Whether you’re building a lowered street truck, coilover-equipped hot rod or custom chassis, a properly designed C-notch provides the clearance needed to get the vehicle lower without simply allowing the rear axle to bottom against the frame.

What Does a C-Notch Do?

A C-notch creates additional space in the chassis directly above the rear axle. When a vehicle is lowered, the distance between the axle housing and frame becomes smaller. Without additional clearance, the rear axle can contact the frame as the suspension compresses, severely limiting suspension travel and ride quality.

Installing a properly engineered rear frame C-notch allows the axle to travel farther upward into the chassis while reinforcing the modified area of the frame. This makes C-notches particularly useful on lowered C10s, F100s, classic trucks, hot rods and custom vehicles where achieving the desired stance would otherwise leave insufficient axle clearance.

More Than Just Cutting a Hole in the Frame

A proper C-notch isn’t simply a matter of cutting clearance into the original frame rail. Removing material from the frame changes its structure, which is why the notched area must be properly reinforced.

Scott’s Hotrods designs its 3/16″ C-notch components to provide the additional axle clearance required by the suspension while creating a strong, properly fabricated structure around the modified frame rail. The result is a cleaner and more professional solution than simply cutting the frame and attempting to reinforce the opening with generic plates.

C-Notch vs. Step Notch: What’s the Difference?

A C-notch creates additional clearance by modifying and reinforcing a portion of the existing frame rail above the rear axle. It’s an excellent solution when additional axle clearance is needed, but the vehicle doesn’t require the extreme suspension travel associated with laying the chassis on the ground.

A Step Notch is a much more substantial frame modification that raises the chassis structure over the rear axle, providing significantly more clearance for vehicles designed around extreme lowering and air suspension.

In simple terms:

Lowered coilover or moderate drop → C-Notch

SuperSlam / extreme air ride / laying frame → Step Notch

The Perfect Addition to a 4-Bar Rear Suspension

A C-notch is often paired with a Scott’s Equal-Length Parallel 4-Bar Rear Suspension when the desired ride height requires more rear axle clearance than the original frame provides.

The 4-Bar controls rear axle movement while the C-notch provides the physical clearance necessary for additional upward suspension travel. When properly planned together, the rear suspension, shock travel, axle position and frame clearance all work as one system rather than being modified independently.

Building an Airbag Suspension?

For vehicles using air suspension, determining the correct rear frame clearance is especially important because the suspension typically operates through a greater range of travel.

For moderately lowered air-suspension applications, a C-notch may provide the necessary clearance. For vehicles intended to sit extremely low or lay frame, Scott’s typically recommends planning the rear suspension around a more substantial Step Notch configuration.

Pairing the correct notch with Scott’s Airbag Equal-Length Parallel 4-Bar—and preferably a Watt’s Link with a Moser M9 FAB housing—allows the rear suspension to be designed around the entire range of travel rather than simply around parked height.

C-Notch Kits for Classic Trucks & Hot Rods

Scott’s C-notch solutions are ideal for a wide range of lowered classic trucks, hot rods, street rods and custom vehicles, including popular Chevrolet C10 and Ford F100 builds as well as one-off custom applications.

Whether you’re replacing leaf springs with a modern 4-Bar, lowering a truck on coilovers or engineering a complete custom rear suspension, Scott’s can help determine the appropriate frame-clearance solution around the vehicle and intended ride height.

Get the Stance Without Giving Up Suspension Travel

Getting a truck or hot rod low is easy. Getting it low while maintaining proper suspension travel is where the engineering matters. When the rear axle runs out of frame clearance, ride quality and suspension performance suffer no matter how good the rest of the suspension may be.

A Scott’s Hotrods C-Notch provides the additional rear axle clearance needed for aggressively lowered vehicles while properly reinforcing the modified area of the frame. Pair it with a Scott’s Equal-Length Parallel 4-Bar and properly selected coilovers or air suspension to build the rear of the vehicle as a complete system.

Whether you’re lowering a C10, F100, hot rod or completely custom vehicle, don’t design the suspension around how the vehicle looks sitting still. Build it around how the suspension needs to work going down the road.

FB-2668, Scott’s Hotrods C-Notches