I believe this ‘engine’ is a P&W mock-up. It has 8 rows of cylinders for a total of 56!
General conses seems to be it's something cobbled together to drag around to airshows. P & W history makes no mention, if it were a real developmental product it would be sitting in a notable museum.
Biggest aero engine ever built in the free world was the Lycoming XR-7755.
https://oldmachinepress.com/2018/05/...rcraft-engine/
