a diesel V6, and a small assortment of V8s, too. Unsurprisingly, the Twin Six wasn't exactly "fuel efficient". The idea for a V12 truck engine came about in the late 1950s. General Motors was ...

When GMC launched the Twin Six V12 in 1961, it wanted to prove that gas engines could stand up to diesel mills in the heavy-duty segment — and, in some ways, it did with its magnificent low-end ...

However, in the late 2000s, Audi toyed with the idea of putting a twin-turbo ... finally, a V12 engine. It leveraged Audi's ...