Rolls Royce Merlin V1650 V-12 Aircraft Engine Specifications:

Packard and Rolls Royce Merlins at other aviation museums in the northeast
Rolls Royce Merlin V1650 aircraft engine at the Vintage Wings of Canada museum in Gatineau, Ontario	Rolls Royce Merlin at the New England Air Museum in Windsor Locks, CT
Another Rolls Royce Merlin Engine at the Canadian Air & Space Museum in Toronto, Ontario	Packard Merlin Engine at the Air Mobility Command Museum in Dover, DE
	Rolls Royce Merlin at the Canadian Warplane Heritage Museum in Mount Hope, Ontario, Canada

Number of Cylinders: 12
Displacement: 1,649 ci
Bore: 5.4 inches
Stroke: 6 inches
Compression Ratio: 6:1
Aspiraton: Bendix-Stromberg PD18 Carburetor, Two Stage Supercharger with Water/Methanol Injection
Fuel: 100 octane aviation gasoline
Weight: 1,690lbs
Length: inches
Diameter: inches
Output: 1,735hp at 3,000rpm
First Flight: 1941
Airframes used on: P-51 Mustang, Late P-40 Warhawk, Spitfire, Hurricane, Mosquito, Lancaster Bomber
Built in:
Cost: $25,000

Here's a Rolls Royce Merlin Youtube video of a Merlin being started and run up on a static test stand at an airshow (Warning - it's pretty darned loud!). One more Youtube Rolls Royce Merlin video showing another big Merlin running on a test stand.