[D.S.I.]

A project in a design class is to create a custom electric powered car to run a 32 ft sloted track, 10 or less alkalines batteries must be in the car, i used a speed 300, 14/46 gr,double 5 series batteries connected in parallel, a brp 18 modified chassis and my time was 3.71s, speed 6.12 mph(i know it is slow but the sponsor was the pinky bunny), the best time was 1.51s(14 mph) it was a 1/24 that resemble a Parma slot drag, full ball bearings, 3v custom-winded gunmetal-color neomags motor very similar to below, but he was just using 4 batteries?, id try 4&5 batteries for weight adjustment but can get any close. Since the car does not uses any electronics I am considering using a stock MiniZ or DTM drivetrain and just 4AA Alka but what motor?
Regards