new to brushless

[BrianG]

Just about everyone here who runs multiple packs runs them in series. For example, an emaxx uses two 6-cell packs (7.2v each), but when wired in series, produces 14.4v. It would be just like having one large 12 cell pack. That's why almost all ESCs have one power input. Some, like the stock emaxx ESC, have two sets of wires, but that is purely for wiring convenience. Internally, the packs are wired in series.

As to what motor you need, you'll have to supply information like how many cells you plan to use, desired top speed, weight of the truck, etc. It would laso be helpful to list the hopups you've done so people can advise where there may be a weakness. Brushless has lots of torque so you have to take the strength of the transmission and driveline parts into consideration. Oh, and your budget would be helpful to know...