99 Cavalier RS GAS, Steel Tank, 44-3/8 x 21 x 9-1/4, Lock Ring Kit Included. 99-2000 Cavalier Base BI-FUEL, Steel Tank, 44-3/8 x 21 x 9-1/4, Lock Ring Kit Included. 99-2001 Cavalier (submodel: Base, LS, Z24) GAS, Steel Tank, 44-3/8 x 21 x 9-1/4, Lock Ring Kit Included.