Castle Creations motor and ESC combo recommendations for the Arrma Notorious.

Monster X w/1515-2200kv - Stock gearing (12/50) on 6s = ~55MPH
Monster X 8s w/1520-1650kv - 14 pinion/50 spur on 8s = ~60MPH
Monster X 8s w/1717-1650kv - 16 pinion/50 spur on 8s = ~70MPH

Note: All speed estimates are with stock tire diameter, high quality batteries and appropriately sized battery connectors.
Always monitor ESC, motor and battery temperatures on new setups or when changing gearing or batteries.