Me, not generally up-to-date- in in the field of Aircraft, et al, always thought that Boeing "Stearmans", were fitted with "Continental" Radial Engines.
The engine in the Photo doesn't look like a Continental Engine...
....eg; the encompassing tube, containing the Spark plug Cables...

....?
Paul...always fascinated with lovely Radial motors!...

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Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.