Hmmmmmm the only one that makes sense is "A". Maybe someone else can help? Reason I say that is my A12 is a 727 auto BUT my '69 GTX is a 4-Speed with a reverse light under the dash AND a tachometer and I "think" both the reverse light wire and the tach wire come through the firewall through the same LARGE hole but up and to the driver's side? Here's an ugly shot of what I think is the hole on the GTX for those wires for the reverse light and tach. Probably wrong on this but hope someone else will chime in.
Mike too
Sorry for the late response ....
Hole A is where the throttle cable comes thru , B is the optional Tach. The reverse lights go thru the bulkhead connected to a wiring harness' empty holes ... same ones as the neutral safety switch for auto trans? ..... check your wiring diagram ...
