What’s a “one-off” anyway? The standard definition is ‘something that only happens once’. For automotive enthusiasts, this word is usually accompanied by other words such as: bespoke, custom, commissioned, coachbuilt. What’s an example of an automotive one-off? Eric Clapton’s gorgeous Ferrari. Or the also privately commisioned Bertone Mantide. These are true one-offs as the firms who designed and built them (Pininfarina and Bertone, respectively) have agreed not to produce any others. That doesn’t mean that every coachbuilt car is a one-off though. In fact, the production numbers of coachbuilt cars sometimes reach into the thousands, while many of their parts are bespoke, and some components actually are one-offs.
Some coachbuilt cars are amazing all-around. Some look the part, but fall short on performance and/or reliability. The ones that are amazing all-around are ordinarily very expensive and are designed, developed, manufactured, sold, and supported by a large manufacturer. The other type are noble efforts of a few individuals or small design houses.
Realizing the immense difficulty in creating a vehicle that meets or exceeds the expectations of today’s customers, it’s not uncommon for an exotic or supercar to have more plebeian underpinnings. These underpinnings are sometimes domestic, sometimes not even from sportscars. While is still somewhat expensive to do so, some coachbuilders and small manufacturers will create a unique chassis, unibody, frame and subframes while borrowing engines and electrical from a donor car.
There’s no shame in it. A ground-up design is shockingly expensive and labor-intensive. Many people looking at the industry would say it’s prohibitively expensive in today’s automotive market to launch a 100% new vehicle.
Perhaps the most well-known example of an exotic with a non-exotic powerplant is the Lotus Elise. Lotus-designed, engineered, and assembled–powered by Toyota.
Consider nearly any De Tomaso one can recall. The Mangusta and Pantera looked all-out supercar but were powered by Ford V8s–even the less supercaresque Qvale Mangusta (nee Bigua) was powered by a Mustang Cobra engine. Maybe even more interesting, the Vallelunga had a Ford-sourced straight 4.
These cars (like those by Lotus) had custom-built frames, specific for them, but (unlike with Lotus) suffered from various faults that resulted in poor driving characteristics and issues with longevity. This brings us back to the advantages inherent in using a complete donor car; a tried and true combination of electrics and mechanicals (with some tweaks, like power bumps) redressed with unique body panels, wheels, interior, etcetera. Less macho than building your own chassis from scratch, but predictably reliable.
Surprisingly, the US-designed and built Corvette has served as the donor for many a European supercar (as well as countless Callaway creations like the the C6, C7, C12, and C16).
Examples of some pretty exotic one-offs and coachbuilts using Chevy underpinnings:
Bertone Mantide (2009 C6 Corvette ZR1)
Clearly, some of these are gorgeously finished and of extremely high quality. There’s no doubt I’ve missed some, so if you’re aware of other interesting coachbuilts, let me know in the comments below!