Ever-tightening U.S. emission regulations were threatening the very existence of the E-type at the dawn of the '70s. The 4.2-liter XK straight-six was at the end of its development so a bore or stroke increase was out of the question. The 5.3-liter aluminum V-12 that was under development at Jaguar seemed to be the answer. It weighed less than the venerable XK six and produced slightly more horsepower than the six had in three carb Series I form.
For the V-12 Series III, Jaguar dropped the two-seater coupe and offered only the 2+2 coupe and the convertible, the latter sharing the 2+2’s long wheelbase. Flared wheel arches and an even bigger, busier grille than the Series II rounded out the cosmetic changes. Performance was roughly restored to Series I levels but the car was far less sporting in nature. Still, it could have been remembered better had it not been produced at one of the worst times for the British auto industry. Series III quality control was less than ideal and the cars acquired a reputation for unreliability. All of the things that afflicted the cars when new can be addressed today (and in fact, most have been over the years) but old perceptions die hard. A Series III E-type does, however, get you into top down V-12 motoring for a fraction of the cost of a comparable Ferrari.