If you want to PM me about this I'll try and look it over with you.
I have not held one of these late model Smiths tachs in my hands but I have corresponded with people about them. I know why Nisonger told you what they did but I'm not sure I agree with them.
Look at the following from the Caerbont (Smiths) web site:
http://www.caigauge.com/page29.html (what they call "older style" tach)
Note comments on white/black wire. (step 3).
http://www.caigauge.com/page30.html (what they call "newer style" tach)
Under "Signal Input Alternatives". The description for the white/black is again specific to a tachometer output from the module.
In both cases ("newer" vs "older" style tach) the white/black tach wire described as being used on connections to a tacho output on the ignition module. Does your Crane module have a dedicated tach connection terminal? If not, I don't think you use the white/black but you DO use the red/blue on coil (-) instead.
Were this my tach, the first thing I would do is confirm that the tach has power (green (+), and black (-)) when the ignition switch is on. Then, I'd connect the red/blue wire to coil (-) (the coil terminal that is connected to the distributor). If you've got power, no dedicated tach output on the ignition module, and you've connected to the correct side of the coil... it should work. If it didn't work under these conditions I'd temporarily re-fit the points and try again just to confirm that the tach itself works.
EDIT: See this PDF from Crane. Look at pages 10 and 11 that show there is no dedicated tach output from the Crane module, the tach connections (red/blue from Caerbont) are still made on coil (-). Now flip over to page 12. That tach installation is for where the ignition amplifier has a dedicated tach output. That's the situation where you'd use the white/black wire.
http://cranecams.com/pdf/90000700.pdf
