Ahhh, so that 'splains it! Never mind.
But there's an interesting conversion conversion that peaked my interest a few weeks back.
FROM INSTRUMENTSRUS. REPLACE YOUR AMP GAUGE WITH AN OIL PRESSURE GAUGE OR VOLT METER!
NOW, YOU CAN FINALLY HAVE AN OIL PRESSURE GAUGE OR VOLT METER TO REPLACE THE AMP GAUGE IN YOUR 1970-72 CHEVELLE, MONTE CARLO OR EL CAMINO GAUGE PACKAGE.
http://www.instrumentsrus.com/gm.htm