The conventional thinking is that PCVs keep the engines cleaner.  But what about drawbacks of the addition of relatively contaminated and heated air into the A/F mixture?  Looking at all the components of a used PCV system usually shows heavy carbon deposits.  I had one late model 2V metal PCV tube almost completely closed from gunk.  Quite a few other OEM aluminum spacers with PCV connection also have been found heavy with carbon like deposit, meaning whatever isnt deposited goes into the cylinders.

The late model 2V manifolds have the gases routed to and from the PCV going only to the front 4 cylinders.  It seems like the front 4 would be lean or the other four rich.  Curious, at least to me.

Is there a tried and true inline PCV that can go between the late model valley with rear cap, and the carb/spacer?  The PCV I am currently using mounts into a bushing at the valley rear.  It produced the same effect as a vacuum leak, with hoses going to each side of an aluminum spacer.  Ended up having to decrease diameter of openings at the spacer to about .180 inches.

I have heard that a PCV has a greater tendency to produce oil leaks from the engine generally, compared to a draft tube.  True False?   

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.