Frank, I think I have all of the wiring diagrams that are out there for a 68 Chevelle, and none of them have the gauge package wiring in them. The only difference from the idiot light panel is that the guages have different connectors. The wire colors are the same on the gauges as the lights. The water temp is dark green (from temp sender) and pink (+ 12v), the amp gauge is black (from horn relay) and black/white (can't remember right now) the tach is brown (from coil -) and pink (+ 12v). The fuel gauge is the same (pink & tan). The connectors are "ignorant proofed" because the way they're made they will only fit on the correct gauge one way. The oil pressure gauge is mechanical and uses a copper tube from the block, through a firewall grommet to the gauge. Hope this helped.
A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more!