The Portuguese Air Force Academy OGMA Chipmunks seem to work pretty well with their Lycoming O-360s. Hard to imagine they don't fly better with 35 HP more and at least 30 lbs less weight. They don't look quite as good but its unbelievable to me that any postwar air force would have operated a low-powered engine that leaks so much oil as an unresolvable flaw in its design, and requires so much fiddly maintenance.
The enlarged Chipmunk homebuilt built in Canada apparently had fatal problems unrelated to the engine but FWIW the six cylinder Continental installation looked pretty good - they redesigned the fuselage for the more modern engine and I think the result was OK visually. I'm sure de Havilland Canada would have done the same and used a contemporary Lycoming O-435 originally if the home office hadn't insisted on them using the old in-house Tiger Moth engine.
PS I saw a Blackburn Bombardier engine for sale recently and it reminded me of a similar thread in which a poster suggested it was the historically logical Chipmunk power upgrade from the UK perspective. If only one had the time and money for all the projects that appeal!
Last edited by Silvaire1; 8th Dec 2014 at 03:43.