The last few hotrod's i tuned to get thru Md. emissions in the mid 80's, higher idle and a lot of timing retard was needed, as was said above. Leaning too much made it worse. I know it's probably apples and oranges as far as the required numbers, but the worse they ran the better.....lol.
Agreed on hot rods...I run an emission station in Texas...When one pulls in running like crap,I know they retarded their timing a bunch and many re adjust in the parking lot after passing as not to over heat...
But with a slant six I think in tune and high idle is the trick...