On Mon, 18 Mar 2013 15:54:19 -0400, 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.

It's probably about CG more than space (or volume).

I never saw tungsten blocks used for ballast when I was an SCCA/CART
tech inspector, back in the '80s. It usually was a plate of steel cut
to fit on the floor, somehow, with a torch.

--
Ed Huntress