[Chris Stewart]

Does it have the old vacuum powered EGR or the new style electric EGR?

The new style electric EGR feeds the EGR pintle position info back to the computer. If the computer sends a "close valve pintle" command and the EGR doesn't report that the pintle is in a closed position because it's blocked or stuck open or the wiring connector is disconnected, the computer will set a Trouble Code 32.
Now here's the sauce...if the Knock Sensors sense a knock, the computer backs the ignition timing off until the knock sensor hushes up. Can you guess what helps keep spark knock to a minimum? Yup, the EGR valve.
Seems the little bit of exhaust gases allowed back into the motor keeps the fuel burn from getting so hot which reduces spark knock AND the production of Oxides of Nitrogen...smog.
This doesn't help power production but when I wanted power, I built a 406 small block and put it in an early Nova instead of dogging out my regular transportation.