I mentioned the valve cover needing to be sealed <the vents at the top> Because a PCV valve will only open when the crankase builds enough pressure to overcome your engine vacuum. The check valve inside it would always be closed if the valve cover vents were not sealed.
Since around '94 I've driven no cars newer than '62 and only had a complaint on the downdraft tube from one which had worn out valve guides which caused an oil consumption problem and subsequently a little smoke out the downdraft tube on startup and when sitting still at idle. I would add a pcv system to an engine that didn't have the valve cover vent myself, but probably wouldn't go out and invest in another cover <unless i already had one around the garage>
I drive my '42 to and from work <which is 45 miles roudntrip> and don't mind mine.
On the 'improved' emissions - That is a bit of a hoax. the only thing that will improve slightly is the hydrocarbons that slowly leak off of the oil <instead they will be adding themselvs back through the tailpipe..If the intake manifold were more efficiant it might make a negligable difference, but as it stands the cylinders don't really burn evenly and you have a rich/lean variation which throughs the emissions of by a whack> I checked mine with a gas analyzer i use at work and it's not horrible, but i tune my carb up with the analyzer regularly.
anyhow, my two cent.
