Regardless of which material you choose for your cage, check the rules of the sanctioning body in charge of the track where you race. In central Florida, most of the local tracks are NHRA sanctioned, so we checked the rulebook to ensure our cage met the minimum tubing thickness requirements in the rules. Generally, companies like Competition Engineering keep abreast of any rule changes, ensuring their product conforms to the latest rule revisions and will give many years of good service. Even so, we used our NHRA rulebook as a reference, along with the instructions that came with the rollcage kit, to properly install our cage. We suggest doing as we did, using the cage instructions as a reference, but installing it by the rules in the NHRA rulebook. If there is ever a question of how or where to install a bar, the rulebook should be the final authority. After all, it's an NHRA official who will be performing the technical inspection at the track, so if the cage is installed by the guidelines in the NHRA rulebook it shouldn't have any trouble passing inspection.
Even though the rules dictate how our rollcage is installed, there is still some leeway to install the cage so it best benefits the race car. By installing certain bars, like the main bar, over key areas of the unitbody frame, significant rigidity can be added to the car. A more rigid car will transfer more power to the back tires, be more consistent, and flex less, which greatly contributes to a long service life. The benefits of a rollcage aren't limited to race cars, powerful street cars will also gain rigidity and consistency with the addition of a cage.
Since we plan to replace our...
Since we plan to replace our glass with clear, lightweight polycarbonate, we decided to go ahead and get the windshield and back glass out of the way.
We began by fitting our bars...
We began by fitting our bars with the main rollbar. The placement of this bar is important as all the other bars will attach to it. NHRA rules say the main bar must be no further than 6 inches from the driver's helmet. With the seat bolted in position, we used a plumb-bob and string to locate the main bar front-to-rear.
To center the main bar side-to-side,...
To center the main bar side-to-side, we simply measured from the bar to the inside of the rear door panel area.
Since our Barracuda incorporates...
Since our Barracuda incorporates a unitbody frame and doesn't have OEM framerails, the rules dictate that all the bars be welded to 6x6-inch steel plates, 11/48-inch thick, that are welded or bolted to the car's floor. These plates were provided in our kit. Instead of welding our main bar to the rear floor, we welded it to the stiffer, under-seat area where it will reinforce our torque boxes, stiffening the area of the leaf-spring's forward mount.
With our main bar located,...
With our main bar located, and the metal plates welded to the floor, the main bar can be tack-welded in place. We've found it best not to completely weld anything until all the bars are fit and tack-welded in place.
With the main bar in place,...
With the main bar in place, we then fitted the main hoop of the cage. This hoop should be as tight to the roof of the car as possible without interfering with the headliner if your car is so equipped. Since our car will see race duty only, we won't run a headliner. In either case, however, the driver's head/helmet should never be above the main hoop while in driving position. Once in position and level, tack the main hoop in place.