The B pack being a smaller motor then the C will only crry a handful of the FT models. Even the C pack radial is a little lacking in power for some of the larger heavier models like the Sportster or some warbirds. That being said you could probably move up to a 4s battery and try that, watch your amps draw though you could burn out the ESC. If you want to stick to 3s, bigger is better. You will need the torque and RPM for those "Oh
!" moments to get yourself out of a pickle. I would say if you like flying you would be better off stepping up to a C pack, you will be building other planes that need it. The recommended Motor size on any of the models is the minimum you need to get any of the particular models to fly. From there you can add all the power you want