My recently purchased 1974 Challenger is lacking oil pressure and temp gauges. They both work somewhat, but seem to only move about 1/2 what they should. Fuel gauge also never goes all the way to full, ammeter seems to work properly. Drove it a little tonight, mashed the throttle one last time before putting it away for winter and the tach went goofy-up to 8 grand when I stomped on it, then dropped back down to ~3-3500 even though the sound said the motor was spinning much faster. Then the headlights went out, but came back on in 2 seconds or so.
My first instinct is a bad dash ground, am I on the right track? Where is the ground for the dash located?