We reinforced the area removed...
We reinforced the area removed by adding 1 1/2 inch-wide, flat strap-steel purchased from our local hardware store. With a thickness of 3/16 inch, we cut the strap-steel to the required length then added small pieces to the sides to fully re-box the cut area, adding more overall strength. We opted to weld in a "skip weld" pattern--welding approximately 1 inch then skipping an inch and welding again. We had hoped this style would keep the connector cooler to prevent warping from heat, but a continuous weld is also an option.
To prevent these types of unwanted movement, a connector was created tying the front and rear subframes together, producing the effect of a full framerail. These subframe connectors reduced much of the body flex and also increased the frame's ability to dampen imperfections, thereby improving ride quality. Since hardtop bodies have a full roof panel adding to their rigidity, convertible models show the most dramatic improvements with subframe connectors.
Many manufacturers offer their own variation of subframe connectors, most of which are a weld-in style that requires nearly irreversible modifications to install. Competition Engineering (80 Carter Dr., Dept. HPP Guilford, CT 06437-2116, 203/453-5200, www.competitionengineering.com) is one company that produces bolt-in subframe connectors, making installation and removal easier while still improving body rigidity and ride quality. With different versions for all '67-02 F-body cars, Competition Engineering's bars are not designed to fit First-Generation convertibles. However, standard hardtop connectors can be modified to fit, giving your convertible Firebird a much-needed structural enhancement.
Prior to any welding, we had...
Prior to any welding, we had taped the strap-steel piece in place to check clearance and modify as needed. Once fully welded, the connector was again positioned and rechecked for contact. If any had existed, light tapping with a hammer would have produced the required clearance.
Here is the final product...
Here is the final product once all modifications were made. The locations of our cuts are approximately 15 inches from the forward end and approximately 13 inches from the farthest rear point. Cuts extend down approximately 1-1/8 inches deep, and once the 3/16 inch strap-steel is welded into place, the thickness of the connector at that point is approximately 1-1/16 inches. We painted the modified area black to keep a uniform appearance and reduce the possibility of rusting.
Included in the kit is a package...
Included in the kit is a package of eight 1-inch-long 3/8x24 bolts and nylon lock nuts. Installation is optional and does require drilling through both the framerail and connector, adding increased rigidity at the front mounting point. Even with a sharp 3/8-inch drill bit, it took several minutes to drill completely through both the frame and the connector. We opted to install only one bolt on each side of the framerail.
Jim Becker, owner of Universal Steering located in Omaha, Nebraska, loaned us his hydraulic hoist, and the experienced team of Brian Carson and son Drew offered assistance modifying and installing the connectors. The task took approximately three hours to complete, including the time spent on the modifications. It is suggested that our measurements be used as a guideline with your cuts made from measurements taken after a mock-up on the vehicle being used. If you are as satisfied as we are with the results, you may begin to wonder why you had waited so long to install some type of subframe connector!
One suggestion we might make...
One suggestion we might make is to purchase at least six new sprung U-clips with 3/8x16 thread pitch. After several years and many miles, the original clips (left) have a tendency to be very weak or broken (middle). We purchased new clips (right) at our local hardware store for less than $1 each, and they are cheap insurance when working on the rear springs. While we had the springs perches down, we opted to replace several of them, also adding new 1-inch-long 3/8x16 bolts and washers which offer peace of mind should we need to remove the bolts anytime in the future.
With the Firebird at its normal...
With the Firebird at its normal ride height, the subframe connectors are visible but not overly noticeable. To the scrutinizing eye, they may detract from the original unmodified appearance, but the body integrity of our '67 Firebird convertible test car has dramatically improved. Car owner Lou Rotella commented on how much more solid it feels under normal driving conditions and how much better it rides with connectors than without.
One suggestion we might make...
One suggestion we might make is to purchase at least six new sprung U-clips with 3/8x16 thread pitch. After several years and many miles, the original clips (left) have a tendency to be very weak or broken (middle). We purchased new clips (right) at our local hardware store for less than $1 each, and they are cheap insurance when working on the rear springs. While we had the springs perches down, we opted to replace several of them, also adding new 1-inch-long 3/8x16 bolts and washers which offer peace of mind should we need to remove the bolts anytime in the future.