I'm familiar with what the EGR system does, and I know on an EFI motor fuel delivery is reduced (and ignition timing advanced) when EGR is flowing, but a carb doesn't know when an EGR valve is open or closed. I'm curious how the EGR was managed on a carb'd engine? It seems to me the thing would have been jetted for the EGR to be open, i.e. lean? Was it open at an idle too? Maybe a temp controlled vacuum switching valve to open it warm? Was it still open WOT?