Excellent post, Carl
One thing that people should check on trucks with significant “ blow by” out the vents in the valve cover: make sure the road draft tube is not clogged with “gunk”. It can be easily removed and then soaked in kerosene or diesel fuel. Other memembers can post advice on a more incendiary technique.
Also, if you do a lot of city driving, or driving under 15 mph, install a PCV valve - that is why Chevrolet put them on delivery vans and on large trucks (and eventually offered them as an option on all trucks). The road draft tube works very well above 15-20 mph, but is of no use at lower speeds.
