RPO U17 - firewall hole size

[rszmjt]

The Oil Line on a 02B Van Nuys Z28 I am restoring is just above the speedo cable retainer clip hole, and it is 1/2" diameter.
Does any one know the correct routing on the interior of the car? Does it go through the firewall mat, or between the Mat and firewall ? Also does it just loop over the heater box and slightly left of the defrost duct? or does it loop under the heater box? Car was pretty original before I took it apart, still has the GM tag on the gauge cluster, and it is ink stamped Jan 23/69  026?
Does any one know if the low fuel warning lite socket plugs into the guage cluster and where? Thanks.

[woodsman1172]

Here's the picture of my firewall, showing the oil line hole just to the left of the Muncie cable entry. Looks like the same location as in Mike's picture, above.