I just got a new one thru a machinist. It was made in Australia. Cost about half what the Chevy dealer wanted to special order an OEM one. Just installed it today along with a fresh timing gear cover.
I wouldn't take any chances with a used one. It's too long since that first production run -- the rubber goes bad, and/or the cast iron in the mounting hub cracks. It could fly off the crank at freeway speeds and lunch thru the radiator.
