After finding the batteries I wanted, I put in a order for what I thought where AA size 3.7v batteries for my 6v battery case. The batteries I got where to big, I had recheck the ebay ad and notice that I over looked the listed measurements.
After sitting on it for a min I took some time to figure out how I was going to make this work..
After 15-20 mins I came up with an idea, I took two over powered Maverick spring that I had, some aluminum foil, and then I was able to fit the batteries within the Stampede and Vulcan's battery tray. After fitting the batteries I finally got the ROF I was looking for, I am very happy with the imported batteries as they where only $15 USD. I'm buying a charger ($10 ebay) for them and will be order more soon..
3.7 volt AA Batteries on ebay
http://electronics.shop.ebay.com/Batteries-Chargers-/48446/i.html?_nkw=TrustF...Battery Chargers for TrustFire brand
http://shop.ebay.com/i.html?_nkw=TrustFire+Chargers&_sacat=0&_odkw=Tr...
Modding springs & parts
http://shop.ebay.com/nerfsprings/m.html?_trksid=p4340.l2562