Anyone got any tips on how to make a fast pinewood derby car for Cub Scouts?

Brand new never opened box, still has the plastic straps on it. The box contains 2 rear springs and 2 front springs, that drops our cars 1". $225. shipped ( U.S. Shipping ) Thanks   http://img571.imageshack.us/img571/6961/dsc02745k.jpg http://img818.imageshack.us/img818/778/dsc02746y.jpg

http://i1097.photobucket.com/albums/g350/apate1973/cars%20stuff/f6c0cc2a-9734-4f3b-82af-31b502ac2785_zpsa7bca0db.jpg

I'm pretty sure this isnt the right place to post...sorry guys. How do I find out what month my car was manufactured? I know the year obviously,but I need to know the month also. The VIN code dosent have that info as well as any of the other code plates on the vehicle. I need to know this so I can order the correct clutch from Grip-force Clutches. I recently ordered one and the pressure plate was 11.5 inches in diameter and my factory clutch is 11 inches in diameter. Is this info available anywh