Ok, this 50 or so pound piece of ballast is really an anti skid device. There's a hunk of iron on the inside of that box, mounted on ball bearings, with springs on each end of the iron hunk to keep it centered. When the car goes around a hard corner the weight moves in the box and then the springs push the weight back to center after the car starts to straighten up. It's a inertia deal and it really does do what it's made to do. A friend put one of those things in a drag car years ago. It not only gave him better traction from the added weight, but it made the car stay straighter off the starting line.
