I really don't know if you need a new gas tank. That one looks pretty decent. Why don't you just have it boiled out at a local rad shop and put it back in. The 9 inch looks okay too. You just have figure out if it's got the gears you want and if it's a locker or equal lock.

Jmho.

By the way, that's one decent looking 55 Ford. Wish I had it.