Ok.. first of all, the current available is the MAH rating of the battery pack. And, that is in miliamps per hour, which is what mah means.

So, if it's a 20C pack, then the max available current, for a short period of time that is, is 20 X the mah rating (in theory) which in this case, is 26 amps. 1300 X 20 = 26000 miliamps or 26 amps.

You may wish to re-figure the battery you want to use if you expect to operate a motor/ESC combination that is capable of 35 amps, and that is if you wish to fly for longer than a few minutes.

CGr.