It appears that GE was working on a redesigned
Z-2177-3 (0528), but was
eventually told to stop the project:
http://dome.mit.edu/bitstream/handle/1721.3/45987/MC665_r14_6M-3674.pdf
Interestingly, nobody told GE to stop - a couple of days ago, while
moving some tubes into the "to sort" pile, I found a Z-2177-3.
A search for 0158 yielded no results.
I might have that number wrong.
--
Will