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Chassis Stiffening Kits
The Proven Innovator - not an imitator!

Quick Facts

  • This is the first step you should take to improve performance
  • Allows your suspension to function properly
  • Decreases frame twist under acceleration

79 to 04 Mustangs have a notoriously weak chassis.  Take a close look at a Mustang that has been run hard.  The doors may not close right, convertible tops do not line up and the alignment shop has trouble getting the car to drive straight.  Road race and auto cross cars can actually get shorter from hard braking.   If you want your car to remain rattle free, strong and you want to get the most out of other chassis and engine mods, you have to connect the frame sections with something beefier than sheet metal.  Sub-frame connectors are a requirement.  They are also inexpensive.  Griggs racing offers several different types:

Lower Subframe Connectors.  79-04 These are an absolute minimum.  They connect the front and rear subframe.

Upper Subframe Connectors. 79-04 These work in conjunction with the lower subframe connectors to form a much more rigid chassis.  Large gains in rigidity are possible due to being tall in a vertical plane.  Think of this like the floor joists in a house.  You could try a zillion 2x4 under the floor, but if they were only four inches deep, such a floor would never be strong.  Yet, a few 2x12’s make incredibly strong floors because of their deep vertical span. 

Complete Frame Kit.  This kit consists of the lower subframe connectors, upper subframe connectors and bulkhead stiffeners.  The upper and lower subframe connectors are then tied together.  Chassis bending (torsional twist)  is reduced as much as 1,500 percent.  These are mandatory for convertibles and are highly recommended for all other coupes.  94+ Street driven Mustangs with power seats may have to switch to a manual adjuster (ford part number) or modify the drivers side upper rail. 

World Challenge Frame Kit.  This works just like the Complete Frame Kit but is different in that the upper frame rails are formed to be fitted lower in the floor of the car and protrude further back though  the rear bulkhead into the rear subframes to make and even stronger car while lowering the seat to facilitate head room for roll cages and a lower center of gravity.  This is a must for safely fitting tall drivers, or for driver-set-back-cockpits in race cars.

Strong but Light  Designed to keep weigh to a minimum while adding the greatest torsional rigidity and structural integrity for safety.  We have been thanked by several drivers that have experienced serious crashes on both street and track in GR40 Mustangs equipped with frame kits and the driver’s compartment did not crush around their feet due to the frame kit.

For more information about how a TorqueArm fits into a complete performance system Please review the following:
"Been There, Done It All" October 2004, 5.0 Mustang and Super Fords
What Are You Going To Do With Your Car
The GR40 Suspension System
"Vortech Mustang Mach 1" April 2004, Motor Trend


    Price   Product Name   Model   Buy Now 
 Lower Flat Subframe Connector ('79-'04)   $109.95   Lower Flat Subframe Connector ('79-'04)   MFK 1000 L  Buy Now 
 Complete Frame Kit ('79-'04)   $349.95   Complete Frame Kit ('79-'04)   MFK 1000  Buy Now 
 Standard Upper Frame Kit- Internal ('79-'04)   $269.95   Standard Upper Frame Kit- Internal ('79-'04)   MFK 1000 U  Buy Now 
 Complete World Challenge Frame Kit ('79-'04)   $497.50   Complete World Challenge Frame Kit ('79-'04)   MFK 2000 WC  Buy Now 
 Lower Flat Subframe Connector ('83-'88 T-Bird)   $129.95   Lower Flat Subframe Connector ('83-'88 T-Bird)   TFK 1000 L  Buy Now 
 Complete Frame Kit ('83-'88 T-Bird)   $434.95   Complete Frame Kit ('83-'88 T-Bird)   TFK 1000  Buy Now 
 Lower Subframe Connectors ('64-'66)   $264.95   Lower Subframe Connectors ('64-'66)   EMFK 1000 C 66  Buy Now 
 Lower Subframe Connectors ('67-'70)   $264.95   Lower Subframe Connectors ('67-'70)   EMFK 1000 C 67  Buy Now 
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Please note: Prices are subject to change.
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