The engine horsepower rating is the most optimistic, and unrealistic figure. Basically the output at maximum rated RPM of the bare engine on a test stand. No loads from gear friction, hydraulic pumps, A/C compressor. Have to compare HP ratings apples to apples, best by pto. Although, if you have the big articulate bareback tractors have no pto, so I believe they will only post engine.
Jenna