The 5.3-litre aluminium V-12 engine was the first all-new Jaguar engine since the 3.4-litre twin-cam 6-cylinder for the XK120, back in 1948. The Series III E-Type was launched in December 1971, and coupe and roadster were on the longer 105-inch, 2+2 chassis.
The body was modified, losing some of the sleekness of the Series I and II cars. The hood bulge was larger, wheel arches became flared, and the open intake was screened with an egg-crate grille. Buyers could opt for slotted steel or knock-off wire wheels.
The 5.3-litre engine was a 60-degree, single-overhead camshaft V-12, developing 272 bhp. Under the hood were four Zenith carburettors and a single 12-cylinder distributor at the rear of the engine’s vee, where it was subjected to fierce heat. Horsepower started out at 272 bhp, good for 0-60 mph in 6.4 seconds, and a top speed of 146 mph, but it was reduced in the US by emissions restrictions to about 240 bhp by 1974. At this time large rubber bumpers appeared for the American audience due to government regulations.
An automatic transmission was optional, and all V-12 E-Types came with power steering. Air conditioning was also optional and often equipped for export markets. The press loved the quiet V-12 engine, but weren’t thrilled by 15 mpg. They were also were critical of the chassis, which they thought was outdated. The interior was praised for the dashboard, gauges and trim, but there were grumbles about it being cramped.
The general complaint was that the car had become a grand tourer, especially as it now cost £3123 in roadster form. Though journalist and Le Mans winner Paul Frere averaged 128 mph across Europe, most cars were bought by older drivers and not driven hard, often suffering from lack of use. E-Type production was divided evenly as usual, and of the 15,287 Series IIIs built, 7,297 were coupes and 7,990 convertibles. About 80 percent were sold in the US.
Both models were doomed after the 1973 petrol crisis. The E-Type could not meet US safety regulations after 1974, but both the roadster and coupe lasted another year in the UK, with the final 50 roadsters painted black, with a special dash plaque.