FYI, someone is selling an empty new battery shell that is made to fit the Optima 6 volt battery. The Optima battery fits inside diagonally. They include the red and green felt rings that commonly go over the terminals to help fight corrosion. In this case they hide the somewhat crude holes made for the battery posts. Woody's Custom shop in Costa Mesa, CA makes the modifications and sells these.
www.woodyscustomshop.com or do a search on eBay for "Cloaking Device for 6 volt Optima Battery looks like an original 6V PORSCHE 356". I bought the case, but am waiting on purchasing the Optima 6 volt battery until my lead-acid 6 volt battery dies.
Lon