This should give you an idea. Somewhere else it says that they can draw as much as 12 amps at 8.4v, but I can't find right away and I'm too lazy to look
SPEED 300 6V Motor GR3306 SPEED 300 6V Electric
Watts...........70
Volts............9.6
Gear Ratio.....5:1
Prop Size......8x6
Amps...........10
Thrust .........15 oz.