Steve,
In my humble opinion there is no way you will ever keep that tank clean. I don't know how difficult or expensive it would be to get a replacement tank in Australia but please look into it. The inline filter pictured above is a good idea but you will be changing that along side the road frequently. I live in Arizona and despite the warm dry climate, once a tank get rusty, it keeps shedding rust particles even after it is boiled out and cleaned. There is a proprietary gas tank process (called Renu) that I used on my Diamond T, which has a unique shaped tank and no one reproduces it. They cut holes in the tank to allow visual inspection while media blasting, followed by braising the holes closed and melting a plastic liner both internally and externally. But this is more expensive than buying a quality reproduction for the Chevrolet trucks.
Kent
