I'd say any 11" head would work. I usually go for a med crown as for me it works with all my banjos. Personally I like 5 star heads, but if I had to guess a Remo head was probably on it from the factory.
It's definitely 11" I just don't know what crown size is on it now, (the original) I like the way it is now, so I want to make sure I get the right crown size. I have heard good reviews of the AMB heads so I was going to go with one of those. I tried contacting Washburn to find out what the original was but have yet to get a reply. I've searched the internet and can't seem to find anything on it. Any way I can find out what size crown is on it now without taking it off?