Like others said, Send it! Mine did the same last time it was on the dyno. There is a chance the single line is contracting or sucking in creating a slight restriction at high rpm; you can put a spring in the line (Call Todd @March Performance) and/or use a larger line. If you have the indy maxx block and have not opened up the lifter valley (cut a hole to create opening or direct line of sight to timing chain) it can cause this as well. Essentially there is no access lifter valley and the lower crankcase once the engine is running. This because the only opening between the lifter valley and crankcase are the oil return holes. The oil return holes are covered with oil shortly after startup and at high rpm the return holes never clear off. Once that happens the oil in the sump is being sucked by the pump but resisted in the crankcase because it is now effectively creating a vacuum.