ohhhh your so new lol
You REALLY don't need a LiPo battery if all you want is 1000rpm.
REALLY. DONT. NEED.
Now your going to ask me why, so here it is;
You can't just slap a LiPo in your AEG and run the crap out of it. As safe as LiPo's are when set up properly, when they're NOT set up properly they ARE a serious saftey hazard.
So not only do you need a crane stock large enough for that battery, but you also need a fuse, MOSFET switch, a voltage monitor, and a LiPo balancer/charger.
So alternatively, you can get just a regular G&P crane stock battery, 8.4v or 9.6v or even 10.8v (they all fit in the same crane stock). They're 2200mah batteries, and I was getting 1000rpm on my old stock G&P at 400fps with an 8.4v 2200mah crane stock battery.
http://shop.ehobbyasia.com/gandp-m4a...ery-black.html