Battery for International Battery Box

Where can I get a 6-volt battery for the International Cub battery box IHS080 so the lid will fit?

Interstate carries a battery for a 56 & up Volkswagon that will fit this battery box and allow you to close the lid.  The Interstate number is MT-19L, it has clearance for the lid and measures 8-1/4" long by 6-5/8" wide and 7-3/8" tall.

JR