Dynacorn 1967 Fastback Mustang Body - Revolutionary Replacement

While over at the Dynacorn body, we put the camera underneath the car for a look. Behind the front wheels are these sturdy torque boxes on both sides. Borrowed from the '68 Mustang design, the boxes even have gussets to further reinforce the structure.

Back at the wheelhouse of the original Mustang, it's easy to see the void left by the absent torque box. The torque boxes were used on convertibles but not on the fastback. While this arrangement is fine for a 289 or 302, the extra reinforcement provided by the boxes would be a welcome addition to a car with a 390 or 428.

Shock towers are another important structural area that should be closely examined. The towers can bend and, without the help of a Monte Carlo bar, travel inward over the years. After 40 years of service, the shock towers can also develop cracks that are difficult to see. Big-block engines and hard use accelerate the process. The previous owner of this car didn't help matters any by cutting open the shock tower with a blow torch just to lubricate the control-arm cross-shaft.

On the Dynacorn body, the shock towers are patterned after the '69 big-block version. Notice how another separate layer of steel jackets the base of the tower, resulting in a much more rigid assembly. This reinforcement also found its way onto Shelby Mustangs built during the period.

When we look into the trunk of the old body shell, we find the standard '67 hinges and a torsion bar to hold open the trunk. The hinges often break, and after time, the bar becomes too weak to support the weight of the trunk lid.

In the back of the Dynacorn body, the trunk hinges are of much heavier construction and patterned after the '68 hinge. The trunk-lid support mechanism has been changed to a coil spring. The weak and rattle-prone torque arm is gone.

The original 1010 automotive-grade steel used by Ford has been supplanted by universal-grade 1006 automotive steel. The new steel is an improved formula with fewer impurities, and it also has better welding characteristics. As we have heard, thicker-than-stock steel was used in the construction of the new Dynacorn body-let's have a look. Here, the core support on our original car shows a thickness of 0.037 inch on the micrometer.

Looking at the core support on the new car, we find a steel thickness of 0.048 inch. The 0.011 increase over stock is certainly a significant amount. A more rigid core support will certainly benefit the front box structure.

We chose the fuel-fill hole to take our next thickness measurement. The thickness of the tail-panel stamping on the new car was 0.043 inch.

We did our best to scrape off old paint and came up with a thickness measurement of 0.034 inch. Once again, the difference of 0.009 inch is a significant amount of improvement.

The car's doorskin thickness was another area of interest to us. The steel thickness on the Dynacorn door was 0.033 inch at the door-handle hole.

The steel in the old door measured 0.035 inch. However, the presence of paint and dirt on the old door may have spoiled the measurement. We suspect the Dynacorn doorskin is at least as thick as the original door. In any case, we can see that the new Dynacorn body is a high-quality offering for the serious Mustang restorer or custom car builder, whether it's used as a replacement for a rusted-out body or as the basis for an entirely new car (which is what we are about to build).