68 barracuda wiring reverse lights and tach

like said the reverse light harness is separate and should plug into to the wiper bulkhead if 4 speed at terms C@D. The tach is fed out a specific hole in the bulkhead.”gray”. The tach harness should be 1 gray out to the firewall and coil - With disconnect and one dark blue to + fuse block. If auto it seems the BU switch is mounted on the floor shifter and or column depending.