Ok I think I just learned something that I suspected was true for some time. I have an late 80's Black Beauty which is a lot heavier than my late 70's Supra. The BB has a B stamped on the shell behind the muffler knob. So the B stands for brass? is that right?
From a very reliable source, I have found out that anything with a "B" stamped is Brass. Bronze is "BZ" or possibly even "BR".