A final alternative is to simply bond and blend the hard fiberglass covers to the body for a custom seamless joint. This approach can give a stunningly clean look, and it is only possible with a hard, fiberglass cover. A drawback of the rigid or even the semi-rigid caps is that any impact will result in body damage, and this is exasperated if a rigid cap is rigidly bonded and blended with the body panels. Considering the hazard, our decision was to assume the risk, and resolve not to slam into anything.
 Originally, the rear taillights...  Originally, the rear taillights mounted through the urethane cover to a reinforcing bracket that was part of the rear bumper assembly. Since the fiberglass cover is so much more rigid, the lenses can be easily supported by the cover alone. Just drill the required bolt pattern to accept the lights. |  The taillight assemblies were...  The taillight assemblies were test-fitted into the replacement fiberglass bumper cap to ensure they are centered in the recesses. No problem with fit here. |  In order to provide the best...  In order to provide the best bond possible, the flange and an area extending about 1/2-inch onto the panel are roughed. We used a carbide bit at slow speed in a die grinder. |
For our project '76 C3, seamless is exactly the look we were after. We are not looking to build our Corvette to anything like stock specs, and intend to carry out many custom modifications. With performance being the overriding goal, using hard fiberglass bumper caps has another significant advantage-the massive impact absorbing system can be deleted for significant weight savings. This modification, of course, carries a safety consideration, since removing the bumper structure negates the impact protection afforded by the manufacturer, but our primary objective here is improving track performance. Gutted of the bumper structure and fitted with just the rigid fiberglass covers, the net effect is at the front and rear; a rubber-bumper car can be substantially lighter than its earlier chrome-bumper counterpart.
For the rear of the car, we passed on a stock, sloped-back, 1976-style cover, and discussed possible optional rear treatments for the car. We wanted a spoiler, but were much more enamored with the clean, one-piece look of the later Corvettes than the add-on look of the Pace Car spoiler arrangement. Tom Keen, of Keen Corvette Parts, had just the cover we wanted-an '80-style cap designed to mate with our '76 Corvette. For the front, a custom '80-style cover is also available, but our goals were bent more toward a custom approach than swapping styling cues over model years. We preferred the looks of the stock front of the '76, though we had some custom mods in mind. If we have one gripe about the OEM front-end styling of our car, it is the massive bumper guards built into the cover, with the front license plate mount pushed up front and center. Since the replacement bumper cap we were going to use is hard fiberglass, it's a piece that can be readily modified by using established 'glassing techniques. The plan for the front was a bonding on a stock hard fiberglass '76 cover, but only after shaving the bumper guards and deeply recessing the location of the front plate.
 Similarly, the flanged mating...  Similarly, the flanged mating surface of the body is roughed for the bond to come. Remove all paint from any area that will receive the bonding agent. |  A trial fit is a critical...  A trial fit is a critical step before bonding. Do not expect a perfect fit, since every body will vary some, but rather look for the best average fit. We worked out the clamping sequence at this stage, and set out all the clamps for quick access to their assigned locations. |  The Mar-Glass reinforced resin...  The Mar-Glass reinforced resin was mixed with its hardener, and then knifed onto the flange of both the body and cover. Make sure to apply enough of the material to fully grip and fill the gap throughout the flange. |