73-87 Chevy & GMC C10 Squarebody Rear Frame C-Notch Kit (Bolt-On)

73-87 Frame C-Notch Kit - #130-4000

The GSI Rear Frame C-Notch Kit is the definitive solution for 1973-1987 Chevy & GMC trucks that require increased axle clearance. When lowering a Squarebody more than 4 inches, the factory frame rail becomes a bottleneck for suspension travel. Our C-notch provides the necessary "relief" to prevent harsh axle-to-frame contact, ensuring a smooth ride even on aggressive drops. Engineered for builders who want a professional-grade foundation without the complexity of a full back-half.

The GSI Advantage

• Bolt-In Simplicity: Unlike traditional "weld-in only" notches that require extensive fabrication and frame stripping, our kit is designed as a precision bolt-in unit. This significantly reduces installation time and allows for a cleaner, more approachable DIY process.

• Structural Integrity: While designed for a bolt-in application, the high-strength steel construction allows for optional welding for builders who prefer a fully integrated, permanent bond for high-horsepower or heavy-duty air ride builds.

• Preserved Suspension Geometry: By allowing for proper upward travel, this kit prevents the "bottoming out" effect common in lowered trucks. This protects your shocks, bushings, and rear-end components from impact damage.

• Complete Installation Solution: We include a custom metal installation template to take the guesswork out of cutting your frame. This ensures your notches are perfectly centered and square every time.

Design & Construction

• Weight: 26 lbs (Total Kit) / 13 lbs (Per Notch)

• Dimensions: 17" x 3.5" x 5" (Per Notch)

• 1/4" ASTM A1011 Hot-Rolled Steel: Laser-cut and formed for a strong, precise fit over the factory frame rails.

• Grade 8 Hardware: Includes (26) 1/2"-13 heavy-duty bolts and Nylock nuts for a secure, vibration-resistant connection.

• Application-Specific: Contoured specifically for the 1973-1987 GM C10/K10 frame profile.

Measurement & Fitment Guide

This kit is purpose-built for the GM Square Body platform (1973-1987). While it is a "universal" fit for this specific year range of Chevy and GMC trucks, please verify your suspension setup before installation.

When to use this kit:

• Rear Drops: Mandatory for rear drops of 4" or greater.

• Air Ride Systems: Highly recommended for all air suspension applications to allow the truck to "lay frame" or achieve maximum drop.

• Static Drops: Ideal for flip-kit setups or lowered leaf spring configurations that experience frequent bottoming out.

Vehicle Applications

• 1973-1987 Chevy C10 (2WD)

• 1973-1987 GMC C15 (2WD)

What’s Included

• (2) Rear Frame C-Notches

• (1) Metal Installation Template

• (26) 1/2"-13 x 1.25" Bolts

• (26) 1/2"-13 Nylock Nuts

• (54) 1/2" Washers

Questions? Contact Us

(480) 940 1806 – Local
1 (877) 951-1890 – Toll Free