[ray_mcavoy]

Yes, some pics would probably be helpful.

Exactly what type(s) of differences are you seeing in the wire color coding vs. the diagrams? Are there wire colors present in the harnesses that aren't even shown on the diagrams? Or is it a matter of the wire colors not matching up with the gauge cluster connector pin-out?

And for reference, a tach, vacuum, or air pressure gauge shouldn't make any difference in the dash wiring harness. The tach (when present) is hooked up with it's own harness that is separate from the rest of the dash harness and the vac / pressure gauges are mechanical.