Our rotor drops about 50 or about the same as the engine, but's that's with a specialty rotor. in 60 bu/ac wheat with a 20 ft. head at about 13% moisture. We pretty much ran the rotor exclusively in the 900 to the 1000 range, with the concaves about 1 and the fan at 1100. We ran the small wire wheat concaves with keystock grates with the vains in the middle position. We also got our dealer to put wheat sives in the combine instead of running our corn sives. We loved it. We have never seen a combine clean wheat so well, with minimum grain loss. So if you don't have them, they are not a necessity, but i would higly recommend them. For now, i would try moving your transport vanes to the middle position. Also, what speed is your straw chopper set on? Make sure its on the fast speed. We windrowed some straw in the slow speed, and that limited our ground speed to about 2.5mph, but when we spread the straw and moved the choppper to the fast position, we could run in the 4-4.5mph range. Hope this helps.