1964-1967 GM A-Body Frame Rail Brace | GF-FRB-6467AB
1964-1967 GM A-Body Mid-Frame Rail Boxing | GF-AE1-FRB
1968-1972 GM A-Body Mid-Frame Rail Boxing | GF-AE2-FRB
S550/S650 Mustang Coupe Chassis Jacking Rails | GF-MJB15
If you’re adding power, swapping drivetrains, or pushing an older chassis beyond stock limits, you’ll eventually run into the same issue:
The chassis starts to flex in ways it wasn’t designed to.
That’s where the new chassis reinforcement parts from G Force Performance Products come in. These components are built to stabilize the structure so your engine mounts, transmission crossmembers, and drivetrain components stay aligned under load.
Chassis reinforcement parts increase the rigidity of the frame or unibody, especially in areas that flex under load.
G Force now offers:
These parts are designed to work alongside motor mounts and transmission crossmembers, creating a more stable platform for modern drivetrain swaps.
Also available:
Jacking rails serve a different purpose, which we’ll cover below.
When torque increases, load travels through the entire vehicle, not just the engine and transmission.
Without reinforcement, flex shows up as:
If the chassis moves, your drivetrain geometry moves with it.
The 1964–1967 GM A-Body Frame Rail Brace (GF-FRB-6467AB) reinforces a known weak point in the front of the chassis.
What it improves:
This becomes more important as torque increases, especially in builds using upgraded mounts and swap components.
Factory GM A-body frames use a C-channel design. That works at stock power, but under higher load it allows twisting.
G Force boxing kits convert open frame rails into boxed sections:
What that does:
These kits reinforce a high-load section of the frame where flex is most noticeable.
The S550/S650 Mustang Jacking Rails (GF-MJB15) are designed specifically to provide safe, repeatable lifting points.
Their purpose:
They are not intended to reinforce the chassis structure or reduce flex under load.
They don’t set driveline angle directly, but they keep it from changing under load.
Driveline geometry depends on:
If the chassis flexes:
Reinforcement helps maintain consistency so your transmission crossmember and mounts stay aligned.
Not every build requires it, but it becomes more relevant when you:
At that point, reinforcement helps maintain consistency rather than chasing issues later.
Transmission crossmembers are designed to:
But they rely on the chassis staying stable.
If the chassis flexes:
Reinforcement keeps the structure stable so crossmembers can perform as intended.
Across most builds, the same issues show up:
Chassis reinforcement addresses the underlying cause instead of compensating for it later.
All products are available from G Force in our Chassis and Suspension line of performance products.
If you’re adding power but leaving the chassis untouched, you’re building on a structure that can shift under load.
The G Force chassis reinforcement lineup is designed to keep that structure stable so your engine mounts, transmission crossmembers, and drivetrain components stay aligned and perform consistently.
Jacking rails help you lift the car safely.
Reinforcement parts help the car handle the load.
Both matter, but they solve different problems.