I have a hydraulic power unit that will supply 7 gal/min of oil at 900 PSI.  I need to know how to size a hydraulic motor (cu. inches of displacement) to match the output of this power supply.  I would like to maximize torque and minimize speed in the application I am using it for.  This will be a certified "farmer engineered and built" item, so I don't have anything OEM to use as a pattern.  Thanks for any help......Mark