My apologises as I was talking from an Advance Design basis. Your 40 may be a problem if you are trying to remain original. Try "Tanks, Inc" as they seem to have steel and alum tanks for many applications at reasonable prices. If you have some 16 guage and a mig welder then make your own. Just don't fiberglass it!
You can always get it boiled out and then weld in a patch. Good Luck.
