73-87 Chevy & GMC C10 Rear Frame Crossmember (Bolt-On)

73-87 Rear Frame Crossmember - # 120-5600

Squarebody trucks are built like tanks—until you cut them up to lay them low. If you've notched or backhalved your 1973–1987 C10, you've likely removed the factory rear crossmember, leaving the tail end of your open C-channel frame free to twist, flex, and stress under load.

This heavy-duty, bolt-in crossmember is the ultimate chassis fix. It bridges the gap between your rear frame rails, boxing the rear section to easily handle modern drivetrain torque and aggressive aftermarket suspension setups.

Forget trying to hold heavy steel in place while guessing at alignment. Our design utilizes innovative internal sliding sleeves that slide right inside the frame channels. They act as a built-in alignment jig, squaring up the chassis perfectly and creating a bulletproof, double-walled connection once bolted down.

Key Features & Benefits

• Designed specifically for 1973-1987 C10 frames

• Reclaims structural integrity lost during aggressive drops and C-notch installs.

• End to C-channel frame flex, bed misalignment, and long-term metal fatigue.

• Bolt-in design with internal frame inlays for added support
  

Design & Construction

• ASTM A1011 hot-rolled steel 

• Precision-cut for consistent fitment

• Internal frame inlays slide into the frame rails for added strength
  

Dimensions & Specs

• Weight: 18 lbs

• Overall Length: 32.5 inches

• Frame Rail Inlays:

  • Height: 4.25 inches

  • Depth: 2.5 inches

• Crossmember Face:

  • Height: 4.5 inches

  • Depth: 2.75 inches

Vehicle Fitment

• 1973-1987 Chevy & GMC C10 Trucks
  

Installation Notes

• Inlays slide into frame rails for alignment & strength. 

• On rare occasions, since the stock frame rails have nothing supporting the rear, they tend to bow in over time, narrowing close to an inch; this will require spreading the frame rails via porta power or another accessible tool.

• Welding not required (can be welded after bolting if desired)

What’s Included

• (1) Rear Frame Crossmember with Logo
  

• (2) 3/8 x 1.25" Bolts
  

• (2) 1/2 x 1.25" Bolts
  

• (4) 3/8 Washers
  

• (4) 1/2 Washers
  

• (2) 3/8 Nylock Nuts

California Proposition 65 Warning

Cancer and Reproductive Harm – www.p65warnings.ca.gov

Questions? Contact Us

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

At GSI Machine & Fabrication, we offer a one-year warranty on all manufactured parts, covering defects upon inspection. However, we are not liable for personal or property damages resulting from misuse of our products. Note that warranties for non-manufactured parts, such as shocks or ball joints, must be handled directly with the part’s manufacturer.

Orders may be canceled before shipment, except for special-order and custom items, such as chassis products and air ride suspension. Refunds for eligible returned items will exclude shipping costs and may incur additional fees. For cancellations or issues with orders, contact our customer support at 1 (877) 951-1890 or sales@gsimfab.com.

Customers are responsible for all customs fees, duties, and taxes on international orders. Once your package is shipped, we are not liable for damage, theft, or loss during transit. Please inspect your delivery promptly and report any issues within 48 hours. For international shipments, local policies may cause delays, and additional documentation may be required. Always ensure shipping details are accurate to avoid additional costs.