That's bullshit but I'll tell you something really shocking so this thread isn't a giant waste.

The name isn't supposed to be Big Zam, it's supposed to be Byg-Zam. If it were "Big", it would have been ビッグ, but instead it's ビグ. And the name is specifically rendered as ビグ・ザム, so it needs a hyphen.

"Big Zam" is a mistranslation.