[Steve Cassani]

The dimensions of the 427 body were dictated by the wider spacing of the parallel chassis tubes, the larger, more oval opening in the front was made necessary by the added heat generated by the larger engine in a still tight and poorly ventilated engine compartment, the flared rear fenders were carried over from the FIA cars but proved inadequate to enclose competition tires on rims at least two inches wider than those on the 289 race cars and had to be partially radiused or flared again, and so on. The final shape of the 427 was more paragmatic than a matter of design; it captures the thinking of the time on how to contain the mechanics of what was the most powerful Cobra, but this time the power derives from a much larger engine and not refined tuning of a small block.

And don't disregard the capacity of the designers and especially the builders contracted to AC to produce the bodies. No one had the money to start from scratch. So they continually modified what they had on hand, using tools and skills that had stood the test of producing an aluminum-bodied car since the early fifties. There isn't much room for imagination or creativity here. Apart from the change to a truly independent suspension and anticipating heavier or more severe loading in some components, not all of which were adequate to the job, the 427 cars are more an evolution of the AC Bristol than looking at the cars side-by-side suggests.

Bob Negstad at Ford deserves credit for envisioning an entirely new car, to be powered by a larger engine. His contribution was compromised when Ford learned AC had contracted for frame tubes slightly larger than those used in the 289 cars, thereby condemning the project to a way of thinking about chassis dynamics that was already over thirty years old. The approach Negstad anticipated was further compromised by demanding that the new Cobra use the 427 engine if it is to attract owners who would otherwise purchase a big block Corvette. Negstad and Ken Miles envisioned a car lighter and more nimble than the folks in marketing and budget believed enthusiasts would buy, knowing the car could not be produced as efficiently as the Corvette and so would cost perhaps as much as three thousand dollars more.

Unlike the Daytona coupe, the shape of the Cobra roadster is more a service to pragmatics than it is a work of art or inspiration. Certainly the original AC Bristol repeated lines and proportions found to be satisfying in the Ferraris of the day; from then on, it was a matter of making a comfortable design work as dollars, partnerships and parts suppliers demanded.