The rear bumpers on the 1958-’60 Corvettes have been a problem since 1958. The styling trends of the day dictated exhaust exiting through the bumper was a very stylish treatment. Many high-end cars in the ’50s used this styling cue, from Cadillacs and Packards to Ford Thunderbirds and, of course, Corvettes.
The problems of exiting exhaust through a chrome bumper became apparent immediately. The bumpers were very difficult to keep clean and the toxic exhaust gases attacked the chrome plating with a vengeance, causing the chrome to flake, leading to rusty bumpers in a matter of years.
Fast-forward 57 years and I am unwrapping two beautiful 1960 Corvette rear bumpers fresh from the Advanced Plating tanks. The thought of running exhaust through now-perfect bumpers defied logic. I had several problems with the factory exhaust arrangement. First, from a styling standpoint, the whole round pipe protruding from an oval hole was awkward at best. Second, due to the size of the hole in the body, exhaust pipe size was limited, making the exhaust pipe appear more like a peashooter. Finally, there was no way I wanted to rust these gorgeous bumpers. But the question remained, what to do with the openings?
We have seen various treatments ranging from simple stainless steel block-off plates to an additional taillight and various exhaust treatments. At first we considered the extra taillight approach but since I had already installed LED brake lights in the factory rear reflectors we felt that might be too many taillights. Then we hit on the idea of a backup light. It would be functional and hopefully we could design them in such a way that they would disguise the exhaust port so it would appear to be a factory option.
After much thought, the actual process proved to be fairly simple. Of course, we were working with freshly chrome-plated bumpers and in hindsight it would have been smarter to do this prior to plating. However, working with the finished bumpers forced us to come up with a bolt-in light, which means this process is totally reversible, and may be a plus if you are considering this modification on a restored car.
We’ll cover this fabrication step by step in the photos, but basically it involves fabricating two stainless steel boxes, purchasing weatherproof LED lights and then bolting the whole assembly to the bumper using the two factory holes in the bottom of the bumper. For lenses we went to our local box store and bought lens material designed for ceiling panel lighting and cut it to size. This material is pretty brittle and very thin so on top of the lens we used a piece of clear Lexan. The smooth Lexan is the outside piece in the bumper.
After we assembled the light and lens in the bumper we were pleased with the result and yet somehow it still looked like a light plugging an exhaust port. It just didn’t have the factory look we were trying to achieve. After some experimenting, we decided the problem was the oval shape, it still looked like an exhaust port. Digging through our box of used Corvette junk (and I say that with the utmost of respect for both junk and Corvettes) we found a somewhat battered piece of stainless steel door panel trim. Hmmm, this might be just the solution.
This stainless steel door panel trim is perfect for adding moldings because it has tabs on the back side that allow you to mount the piece by simply drilling the holes and then folding over the tabs. We carefully cut the piece of trim for a perfect fit, drilled two holes in the lens and then folded over the tabs. In our case, we had to sand, polish and buff the trim since it was deeply scratched. To save that effort you could simply order a new piece of door panel trim from your favorite supplier of reproduction Corvette parts.
In the end, the divider bar did the trick as it visually changed the shape of the opening, and we have successfully disguised the original exhaust ports, and as a bonus we also have full-functioning backup lights. Thanks to our Lokar shifter and the shift indicator module we used while wiring the car, connecting power to the backup lights was pretty straightforward. The LED lights come with a ground and a hot wire so there was no need to ground our fabricated light housing. If you are using a factory shifter you must provide a switch to power the lights when the shifter is in Reverse, or you could simply mount a switch somewhere and manually operate the backup lights.
Follow along with the photos for a step-by-step process and maybe you can add a special twist of your own to the basic concept of backup lights in Corvette bumpers. The options are many, you could use red lens material for additional taillights or as additional brake lights only, or you could use the clear lens material with the red LED lights in the housing, the options are many and almost anything is better than running exhaust around that pretty chrome.
01. The design process begins in poster board form, it is much easier to make changes with a pair of scissors and tape than it is with metal, a shear and a grinder.
02. After arriving at the proper size, this simple template was cut out of poster board. The light box cannot be too deep or it will hit the body.
03. Our box measured roughly 1 3/4 inches deep, but this may vary depending on the thickness of the lens material being used.
04. We also cut out an oval pattern to fill the exhaust opening and then we test-fit both pieces in the bumper. Certain everything would fit, it was time to start cutting and forming some stainless steel.
05. We used our poster board templates to cut out the blanks and then our Woodward Fabrications metal brake made short work of making the required bends.
06. Here is the formed light box and the oval piece of stainless steel that fits the exhaust port opening perfectly.
07. We used our Miller Synchrowave 200 TIG welder to weld the corners of the box and to weld the oval plate to the box. A series of short welds minimizes distortion.
08. After a little grinding and filing, a test-fit of the assembly indicated everything was going to fit quite nicely. We had to be very careful working around our beautifully replated bumpers from Advanced Plating.
09. We cut a slot in the face of the light box after the welding was complete with a cut-off wheel and a die grinder. The stainless steel plate was visible through our lens, but a coat of gray/green primer helped camouflage the plate.
10. The next step was to form the lenses for our backup lights. We used Plaskolite prismatic clear acrylic light panel material for the lens, purchased at the local box store. However, this lens material is very thin so we put it behind a 0.093-inch (7/64-inch) thick piece of clear Lexan.
11. After cutting out the basic shape, we used a disc grinder with an 80-grit pad to form the final shape of both lenses. Be careful with the thin lens material and work slowly as it is very brittle.
12. We did several test-fits of the lenses in each bumper. Each side proved to be slightly different to accommodate irregularities on the inside of the bumper.
13. This shows the basic components of our light box before we welded the faceplate on the box. So this is the order of assembly, and note the Lexan is the outermost piece.
14. At first we were concerned with how to mount the light box in the bumper. Happily, Chevrolet provided two counter-sunk holes in the bottom of the bumper. We formed these simple brackets from stainless steel angle and drilled and tapped them for 1/4-20 bolts.
15. The angle brackets simply push up against the light box, holding it firmly in place. Now that we are sure everything fits it is time to install the actual lights. Note the grommet in the housing for the wiring.
16. Modern lighting is amazing; there are so many options. We chose a flexible string of all-weather LED lighting in bright white. You could use red LED lights if a taillight is desired. We wrapped the lights in the housing in a serpentine manner and held the string in place with several dabs of clear silicone.
17. And here is the first “finished” light. We liked the look but somehow it appeared to be a light filling an exhaust port. We wanted a bit more style and disguise.
18. We decided on a stainless steel divider strip, and after we located a piece of door panel trim in our spare parts bin we cut the piece to size. These strips are available in reproduction form, too.
19. We had to sand, polish and buff our old piece of stainless and then carefully fit it to the Lexan and lens. Finding the center of the oval proved to be an “eyeball” decision as mathematical center did not look right.
20. The cool thing about using the door panel trim is it comes with fold-over tabs so mounting it to the lens was a simple matter of drilling two holes and then bending over the tabs.
21. Here is the final installation. The LED lights are mounted inside the light housing and the divider bar does a great job of giving the bumper opening a new look. We were real happy with the finished product. It should also be noted the entire light conversion is reversible so even a restored car could use this treatment.
22. Prior to installing the bumper, we tested our new lights and were pleased with the amount of light the LED backup lights produce. In our not-so-humble opinion the new lights look like something Chevrolet could have offered in 1960.
23. We had the original license plate light covers replated by Advanced Plating because their chrome is far superior to any reproduction part chrome plating. Before we sent them to be replated we removed the four small rivets to remove the lens and bulb housing.
24. Rather than install new rivets in our freshly plated pieces we simply clamped the bulb socket plate in place and mixed up a little JB Weld to hold it all together. The original lenses cleaned up perfectly.
25. Two Philip head screws hold the license plate light in place. We left enough wire on the bulb and ground wire to extend inside the body through the original hole and grommet.
26. Let there be light! Sure enough, when our Lokar module is moved into Reverse the backup lights come on. The license plate lights come on with the light switch and we used Corvette Central LED lights in place of the stock red reflector as third (and fourth) brake lights. This completes the rear lighting on our Corvette and it is all modern LED lighting.