[suicideneil]

You ask too many questions :) The batteries should be treated like 1.0v per cell underload when doing your calculations. 1940 motor will be plenty, and you can can plumb in the different gear ratios / motor turns into the speed calculator to come up with some answers. Just remember that 40,000 rpms is the target motor speed, and 40mph is plenty of speed vehicle wise- adjust gearing/ voltage to match really.