Abstract: A kiln car which permits a substantial increase of product throughput per car per day through a kiln is disclosed. The kiln car includes a carriage for conducting the car through the kiln and a superstructure made of reduced mass of dense refractory components. A lower load-bearing base is arranged and constructed so that the load-bearing surface lies in a plane below the plane of the bench of the kiln to provide an increased cross sectional area for product firing. The low-mass, load-bearing base includes a plurality of spaced, dense, refractory blocks which are resistant to thermal shock, and capable of withstanding temperatures of about 1300.degree. C., and are positioned around the perimeter of the carriage, with each block having a bore or socket for mounting a refractory column therein. A plurality of elongated dense refractory members or spacers are positioned around the perimeter, and are mounted between the refractory blocks to lock the blocks in place.