Actually the reverse. Weight in the tail.... as far back as you can get it. Wheels as far apart front to back as possible. Wedge shape.
Turn the axles with a file and drill. Ream the wheel holes and coat with graphite. Run the wheels in on an a specific axle for 5 minutes while adding more graphite.
Pack Winner and District winner for 3 consecutive years
My daughter made sure weights were place behind and directly in front of the rear axles. Perfect placement. Shape was flat ... maybe a quarter inch thick. Polished axles and lots of graphite.
I hate the graphite.
I was winning all the early heats. Then somebody said to add this graphite stuff, “It’ll go really fast.” I said no but got talked into it.
Of course I came in last (by half the length of the track) in the championship race. The graphite loosened up the glue holding the axle nail into the block of wood. The glue ran down into the tires.
I was one ticked off little kid.