"Something that you might want to consider is to fill the vents on the valve cover, then add a fitting to the valve cover and one to the top of the air cleaner. Connect the fittings with a rubber tube. That will allow the engine to breathe clean air that has been filtered through the air cleaner.
If you want to keep the vents looking cosmetically the same (but closed), I remember reading a post on this forum that someone had filled the openings with JB Weld, then sanded them smooth. I thought that was a good idea when I read it. I seem to recall that others have filled the gaps with silicon. I have seen several conversions with the vents pounded closed and then brazed shut."
Matt,
Thanks for those suggestions. I'm trying to think up a way to allow breathing through the original valve cover louvers to keep a look as original as possible while also filtering the air
So far the three approaches that have come to mind are inserting a piece of air filter medium into each ,louver like a piece of TP in a nostril for a nosebleed or making a bracket that attaches to the valve cover studs to hold filter medium over or under the louver openings. Mounting the filter medium inside the valve cover would hide it but would require some clearance between the rocker arms and the inside top of the valve cover. The inside mount option would also require removal of the valve cover and replacement of the cork gasket to check or replace the filters but it would have the plus of the filters being completely hidden, a true "stealth" modification. The outside bracket/filter option would make checking the filters and replacement when dirty easy but would be a really in your face deviation from the original appearance.
Hiding the PCV valve doesn't seem possible but it would be in an inconspicuous location low on the block behind the oil fill/draft tube. I would keep the original draft tube but block its bottom opening with a 1 3/16" freeze plug. The PCV valve would be mounted in a grommet inserted into a piece of 1 1/4" tubing mounted perpendicular to the draft tube facing towards the rear of the engine (a "T" connection of two 1 1/4" tubes).
"Can anyone explain if it’s not working property after installed how we will know?"
Don,
The Deves write up indicates that crankcase vacuum should be between 1" and 3". So measuring the vacuum through the oil dipstick hole per the Deves method would reveal whether you within those limits. An adverse effect on engine performance would be an indicator that something is not right as would decreased performance of anything that requires vacuum (windshield wiper motors, brake booster, AC/heater controls, etc).