Well it's not exactly american muscle anymore, but it's still freaking awesome and those tires look insane.
Engine was designed and pretty much made by Ford, aston martin is owned by Ford.
Here you go, from Winkpedia:
The Vanquish's V12 engine shares some components and design elements with the 3.0 L Duratec 30 V6 from parent-company Ford. It even shares the same bore and stroke dimensions. For this reason, many people incorrectly dismiss the Aston Martin V12 as merely "two Duratecs linked together."
The V12 engine in the Vanquish was designed at Ford Research in the USA. Cosworth Technologies was originally contracted to manufacture the engine, but had no involvement with the design. Previous articles which correctly recount this engine's development have appeared in Automotive Industries magazine.
It is correct that the AM V12 shares components with the 3.0L 'Duratec' V-6 engine used in the Ford Taurus, but it is not possible to simply put two V-6's together to make a V12. The bank offset for a V12 is equal to one rod bearing width, whereas the bank offset for a 60-degree V-6 is significantly longer than one rod bearing width, thus it is necessary to design a V12 as a totally new engine.
