I just bought a new 8 hp b&s intek I/C engine for my splitter. My hydraulic pump is an old 19 gpm single vane pump by vickers. It is belt driven from the engine. The documentation for the pump states that 1600-1700 rpm is maximum operating speed for this pump. It has a 5 1/8" pully attached to it. My new engine will spin at 3600 rpm. What size pully do I need to gear down the operating speed for the pump? Will excessive speeds be detrimental to the pump over the long or short term? My last engine was an old wisconsin that chugged along at a slower pace so the pullys were of equal size. Thank you for your math skills.