5.5 Weight Limit

[ohiofitter]

My next door neighbor just brought over a milled piece of steel as a mold to use to melt lead in.. We just melted the lead made 2 nice forms and his boy has to glue them in and his car will be done. His son's race is next Weds. they were giving a derby kit and rules that state 7 1/2 inch long and 5 1/2 onces of weight. I explained to my neighbor boy about the com and how it makes the car faster.Where should we put the com be for this type of race.... We made a tung to glue to either the front of the car (to push the weight up the track another 1/2 inch) or the back of the car if the curve is to sharp.