[1969_CM2590D]

Yes, the vacuum gauge. Dad had to rent a '75 Impala from the dealer while our '72 Impala was getting accident repairs done. The '75 had a "fuel economy gauge" that rattled and quivered while you drove. Pretty annoying. The gauge face told you whether economy was poor or excellent as the needle moved. A gimmick in the wake of the '73 oil crisis. It flanked the speedo opposite the fuel gauge, replacing the clock. I asked Pop how it worked. He answered, "Oh, it's just a vacuum gauge" and I learned a little something.

I've always thought "Oil Temp" would be more useful in that hole in the truck cluster. Or if you have rigged an auxiliary tank setup- a second fuel gauge.