@halifaxhops after some extensive research, it appears that both the slant 6/904 pb gear select cable has the same part number as the 318 Poly/727 pb gear select OE P/N: 2266 403.
Thank you! I haven't quite got it out to measure yet. I have to pull some carpet etc. But thanks to you, I would love to talk to someone about any /6 cables that might be laying around then. ha