An American ex-racing driver, Carroll Shelby, changed its fate. In 1963, ten years after its launch, Shelby helped AC modifying the car. He put a 4.7-litre Detroit Ford V8 under the bonnet and modified the chassis slightly to cope with the heavyweight engine. The result was more than anyone would have expected. Power was dramatically increased to 271 hp, zero to sixty could be done in a mere 5.5 sec and had a top speed of 138 mph to match. Moreover, the already outstanding chassis was given the necessary power to demonstrate its ability.

Since the Ford V8 came from the fast-selling Mustang range, cost could be minimized. Furthermore, when Ford introduced a larger V8 in Mustang and GT40, AC Cobra also benefited from it. Therefore, in 1965, the mighty Cobra 427 was added, which had 427 cubic inches capacity, or 7 litres. With 425 horses underneath the bonnet and a relatively lightweight body, it easily became the fastest accelerating car then. However, due to the shortage of supply of this motor, many of these 427 were actually fitted with 428 engines, which was derived from the "police car" Ford Galaxy and was capable of "only" 355hp. Shelby said the differences between 427 and 428 in real world were hardly noticeable.

The Cobra enjoyed huge success in the USA. Both 427 and 289 (i.e., the original 4.7 litres or 289 cubic inches version) sold good there. Today they remain as one of the most favourite classic cars. The 427 had a mightier image purely due to its fire-breathing power, while the 289 was lighter, better balanced and crisper to handle, provided the best overall combination.

Vantage, the James Bond car, was already powerful enough with a 405 hp 5.3-litre V8. In Zagato, enlarged exhaust system and modified Cosworth valves and pistons were employed to increase the maximum power further to 432 hp. Moreover, the original 2+2 floorpan was shortened to become a 2-seater, thus cutting 168 kg. All these added up to the dramatic enhancement of performance - top speed 186mph, 0-60 mph in 4.8 sec. Apparently, Aston finally created a world class supercar.

Zagato was fairly rare, with only 50 coupe and 35 cabriolet (Volante, in Aston's words) were built. Except the plane outlook and the excellent 0.31 drag coefficient, it followed the tradition of Aston in every ways - fast yet luxurious, with abundance of high-quality leather. It was very powerful, but also very heavy (especially concentrated in the front axle), thus relatively bulky to handle. Use of technology was also regarded as too conservative by supercar’s standard.

Quattro was so perfectly engineered that even its second generation could not match its pure steering feel. Therefore it is still regarded as the best Audi ever built.