Bob Engelhardt wrote:
35 lb tungsten "ballast" blocks (race cars): $1877

http://www.stockcarsteel.com/tungsten/

Twice as dense as steel & 50% more than lead, but what a price to pay
for the little space that it saves.

Allows you to play with weight distribution easier than larger chunks of lead/steel.

You build the car as close as you can to the weight distribution you want BUT you build it
light. Then you add weight to put the extra where it will do the most good for the type of
race and still come up to minimum weight with an empty tank.

--
Steve W.