Shelby American's original intent for the 427 series of cars was, obviously, to provide more horsepower in the Cobra. It is said that the Shelby team had pretty much extracted the most power that they could from the 289 Ford engine, so more cubic inches was the logical progression. To cope with the additional horsepower (and weight) the chassis had to be strengthened which was the basis of the change to the 4" diameter chassis rails. Additionally, the front and rear suspension was also modified for improved handling by changing to coil springs and revamped A-arms and trailing link geometry.
The following pages provide a short summary of our 427 Cobra, CSX3193
CSX3193 is one of approximately 350 Cobras originally built by AC Cars for Shelby American in 1965. It was one of the last of the initial contract (for 100 cars) between Shelby American and AC Cars. The 427 Cobras have chassis numbers CSX3100 through CSX33?? and although all are referred to as 427 Cobras, only the first 100 (approximately) chassis actually had the Ford 427 cubic inch engine. The remainder of the "427" production utilized the slightly less expensive ford 428 cubic inch engine. The original 427 Cobras also were broken down into what is now referred to as "SC" (street / competition) and "street" cars. There is also sometime a further breakdown of the 427 body referred to as "narrow fender" and "wide fender" referring to a minor difference in shape of the rear wheel arches.