It occurred to me as I've been working on the C5 GTO that this project is different from most other car projects. Classic hobbyist cars for the most part fall into one of several categories-street rod, muscle car, kit car, supercar, for example. Most projects in the kit car category generally follow one of three tracks: exact (or nearly so) copies of an original, faux look-a-likes on VW, Fiero, or other such modular factory car platform, or original designs not replicating any one car in particular. The common theme for the street rod category is a large V-8 in a car of U.S. origin made sometime before 1950. For muscle car category, it's a large V-8 in a mid to large size two-door sedan that usually had great straight line acceleration but left something to be desired around the curves. Then there's the supercar category-McLaren F1, Ferrari Enzo, Bugatti Veyron, Saleen S7, Ultima GTR, Mercedes-Benz SLR McLaren-that are more often found in people's fantasies rather than a hobbyist's garage.
What's different about my project you ask? It doesn't fit in any of the typical kit car variations or in any other category for that matter. It's not really an exact replica. It looks similar to a Ferrari 250 GTO but with a wider body and track. It has wide, low-profile performance tires that give at least twice the footprint of original GTO rubber. Yes, the Columbo design SOHC 3-liter Ferrari V12 was very advanced for its time and dominated GT racing circuits in the 1950s-'60s. But 50 years of automotive engine technology advancement made it an easy decision to go with a modern Chevy LS1 V-8 that dollar for dollar churns out an order of magnitude more horsepower. Yes, the factory LS1 output of 345 hp would be plenty for most cars, but I felt the C5 GTO deserved to be in the 500 horsepower range with an inter-cooled supercharger along with conversion from pushrod valvetrain to SOHC. The C5 GTO is a car that will catch the eye of any Ferrari aficionado, but will likely cause a Ferrari purist to shake their head in disgust while muttering something about how this car taints the grandeur of the Italian marque.
One day while pondering some project decisions, I asked myself what criteria should be used to judge a good decision versus a mediocre or bad one for this project. It then occurred to me that most criteria are typically determined by the automotive category. If you're building a faux look-a-like, then you go extra lengths to copy small details to fool onlookers. If you're building a street rod, then you use a V-8, not some little foreign-made four-banger. If you're restoring a muscle car, you buy NOS parts with the factory labels still on them. But what if you're building something that doesn't fit an existing category?
In retrospect, the C5 GTO project has been on an unwavering design trajectory to-date, even if I didn't have an existing category to use for decision guidance. What is it that's serving as a compass for this project? It then occurred to me that maybe a new category has been emerging over the five-year project time span here at Last Chance Garage. I don't know for sure, so I thought I'd put it out to you the reaader and see if it has merit.
Retro is an automotive design trend that's taken hold and seems to have become mainstream over the last few years. How else can you explain the overnight popularity of the new Ford Mustang that definitely takes its styling cues from 1960s era Mustangs? Or the new 2008 Chevy Camaro that takes distinctive styling cues from first generation Camaros? I look at the Chevy Camaro tag line, "When you're really good in a past life, you come back as yourself" and it tells me retro has some staying power in automotive design.
Supercars are the subject of many fantasies, but in reality are rarely wholly possessed in any one automobile. The definition for supercar from Wikipedia is, "A supercar is a term used for a sports car, typically an exotic or rare one, whose performance is highly superior to its contemporaries. The proper application of this term is subjective and disputed, especially among enthusiasts." The definition then goes on to say that it's really performance criteria that sets a supercar apart from the crowd for things like power-to-weight ratio, acceleration, top speed, stopping ability, and handling. It's also noted that supercars are street driven and thus are not purpose built racecars.
So let's compare the C5 GTO design targets to accepted supercar benchmarks. I'm estimating the C5 GTO with its supercharged 5.7-liter LS1 will have 500 hp and weigh in at 2,400 pounds. for purposes of this comparison. This power-to-weight ratio should provide ample acceleration to meet or exceed the supercar benchmark. 500 hp nestled in a sleek, aerodynamic body style that clocked 175mph with only 300hp down the Mulsanne Straight at Le Mans should easily enable the C5 GTO to crest 200 mph. The C5 GTO is outfitted with 245/40ZR19 front tires and 275/40ZR19 rear tires, which put 9- and 10-inch wide rubber patches on the pavement. This along with modern C5 Corvette suspension on a rigid tube chassis is key to high g-force handling. The 13-inch front and 12-inch rear disc brakes, which are oversized for car weight, should make for great stopping power. In reality, all these things must come together to achieve supercar level performance, but for now let's assume it's achievable.
What happens when you add retro styling to what's probably best described as a homebuilt supercar platform? Might it be the start of a retro supercar category? In hindsight, I now see the blended characteristics of both retro and supercar are the compass behind the C5 GTO project. While all this now seems quite obvious to me, I felt the retro supercar question really needed an answer from a much broader audience to have any credibility. The more I've thought about the emergence of a new hobbyist car category, it seems to make a lot of sense. But, I'm far too close to the C5 GTO project to have an objective viewpoint.
Assuming I'm on to something, the next logical question is: is the Retro Supercar category big enough to potentially fuel interest and major growth in the kit car segment? The last major kit car growth wave was fueled by Cobras. Cobras have been a very good thing for the kit car segment (I'm also not very objective here either, as I built and still own a Cobra), as the majority of them are truly high-quality automobiles that both look great and have exhilarating performance. What the kit car segment needs now is another similar growth wave if it is to truly break out from the legacy of dune buggies and simple fiberglass bodies on VW pans. Not that there's anything wrong or bad about the legacy, but people's automotive technology expectations have moved on.
Some may ask if Cobra roadsters wouldn't also fit in a Retro Supercar category. While Cobra styling does fit the retro part, I'd dare say Cobra roadsters will likely fall short in one key factor: top speed. I don't think you'll see a Cobra roadster break 200 mph, unless the Cobra has considerable ground effects added to its non-aerodynamic body. The Cobra Daytona coupe does appear to have the aerodynamics to beat the supercar benchmark in this department, though. Recently I've seen a few Daytona coupe examples that claim 500-plus horsepower that will likely also meet/beat the other supercar performance benchmarks. So a legitimate question is: are Cobra Daytona coupes a second example supporting a new retro supercar wave? I'm guessing only time can answer that question, as it takes more than two examples to form a category.
What other car designs might also fit into a retro supercar category? There are many 1960s era sports cars and GT racers with classic sports car looks that would need a modern technology boost to meet supercar performance benchmarks: Jaguar E types, Aston Martin DB4, Corvette, Ferrari, and Porsche being several examples. The Ford GT40 has become popular in kit car ranks, but that particular car met supercar performance benchmarks in its original form. So, newly built GT40s might be considered a supercar, but would seem to me to be more exact replica than Retro Supercar.
It's time for you, the KIT CAR reader to let your opinion be heard. Are you ready to embrace a new wave in the kit car hobby? Does the combination of retro styling and modern automotive technology applied to deliver supercar performance pique your interest? Beyond that, does the idea of retro supercars excite you? Do you have an urge to have a retro supercar in your garage? If so, what retro car styling do you find appealing? Of these, which also have the aerodynamics to be a candidate at supercar performance? If you don't think retro supercars will form the next big kit car wave, what will?
It's time to let your opinions be known. If you have an opinion, then let everyone know what it is by posting a blog on the www.kitcarmag.com web site. We are very interested in what people at the grass roots level of this hobby think this can fuel and maybe even propel the hobby to new heights.
| Supercar Factors | Supercar Benchmarks | Supercar Examples | Corvette Z06 (C6) | C5 GTO Targets* |
| Power-to-weight ratio | < 5lb/hp | 1991 McLaren F1, 4.01 lb/hp | 6.2 lb/hp | 4.8 lb/hp |
| Acceleration, 0 to 60 mph | < 4 seconds | Enzo Ferrari, 3.4 seconds | 3.5 seconds | 3.2 seconds |
| Acceleration, 0 to 100 mph | < 10 seconds | Enzo Ferrari, 6.5 seconds | 7.9 seconds | 7 seconds |
| Standing Quarter Mile | < 13 seconds | Enzo Ferrari, 11.1 seconds | 11.8 seconds | 11 seconds |
| Top Speed | > 200 mph | McLaren F1, 231 mph | 198 mph | 201 mph |
Acceleration/
Stopping, 0-100-0 mph | < 12 seconds | Enzo Ferrari, 11.7 seconds
Saleen S7, 11.2 seconds | | 11.75 seconds |
| Handling | >= 1g | Enzo Ferrari, 1.01 g
Saleen S7, 1.10 g | .98g | 1g |
The Cobra Daytona coupe is a recently emerging example car that might also fit into the retro supercar category.
* These are projections based on design and partially-completed car. Actual performance won't be known until car completion and testing.