V12
On March 21, 2007 it was reported by AutoWeek that GM was planning to develop a 60-degree V12 based on this engine family to power the top version of Cadillac's upcoming flagship sedan. This Cadillac would essentially have had two 3.6 L High Feature V6s attached crankshaft-to-crankshaft and would have featured such high-end technologies as direct injection and cylinder deactivation. If so, the twin-engine would have displaced 7.2 liters, and produced approximately 600 hp (447 kW) and 540 lb·ft (732 N·m) of torque. Development of the engine was reportedly being conducted in Australia by Holden.
In August, 2008, GM announced that development of the V12 had been cancelled.
Read more about this topic: GM High Feature Engine