First off, i used to be gabriel3366 but I changed my name.

Anyways so i made my own hump pack, it is 1450 mah, 6v and it is made out of 5 aa batterys. I was suprised by how powerful it was, the increase in power is huge The servos turn much faster and stronger.
I have yet to actually drive it with the pack but i will make an update when i do.
Here are some pictures:

Tmaxx spring for size comparison:

Yes I know the soldering is not pretty