Before you lot go bagging the infamous Rolls "Merlin" Just remember it started life with under a thousand horsepower, and ended its career with well over 2000 HP and quite reliablely albiet on the noisy side. It still holds the world record for a piston aircraft engine with the highest BMEP, and also with the small capacity of only 27 litres ( 1650 cubic inches) to you imperiallists, whilst others of the American and German counterparts engines were in the range of 45 to 55 litres and more. Rolls Royces main tributes to this high output/ small capacity was excellent supercharger and intercooler technology. Interestingly, Rolls never went to turbochargers as the Americans/ Germans did.....their argument was that on the later engines with efficent ejector type exhaust stubs that the exhaust pressure created about 150 Lb's of forward thrust.........Greg.