10,000 easy if well maintained...if not its all over the board.
Man!.... you must have an "Oil Can Henery's" work pit under that Perkins.. ..Im envious.One of the features I like about the Perkins is ease of rebuilding. The cylinders are sleeved, assuming reasonable elbow room, you will not need to remove the engine for a rebuild.
I've no idea how many hours it has on it, original meter is gone. It starts instantly and ticks along nicely, using no oil.