The airforce used to run a lot of those Cesna centerline thrust pusher/pullers. That was one noisy bird to be inside! The mechanics never worked on the Lycomings, they just replaced em. I think they were Six Cylinder 400 CID engines. Somewhere around 300 HP per engine. The engine swapping phenom produced a lot of "serviceable but not airworthy" engines during the 70's. They used em on airboats, television sets for creating high winds, and as you said, many other uses. Today a run-out engine core fetches $6,000 to $10,000 a copy. How times change!
"Today a run-out engine core fetches $6,000 to $10,000 a copy. How times change!"
And not to mention what a rebuilt engine costs.