8V71 Detroit Diesel Engine Specifications Published in MOTOR DIESEL REPAIR MANUAL, 1979

Engine	HP @ RPM	Torque @ RPM	Injector cu. mm.	Comp. Ratio
8V71N	242 @ 1950	696 @ 1200	55	18.5
8V71N	265 @ 2100	732 @ 1200	60	18.5
8V71N	289 @ 2100	758 @ 1600	65	18.5
8V71T	293 @ 2100	892 @ 1200	65	17
8V71T	320 @ 2100	941 @ 1200	70	17
8V71T	335 @ 2100	967 @ 1400	75	17

Unless you have access to a dynamometer, the horse power and torque ratings of your engine can only be an educated guess based on published ratings.