Originally Posted by
mr_ranger-79
Does it matter which valve cover the pcv valve and breather is on? I didn't think it made a difference...does it? Will lack of vacuum or vacuum leak prevent the truck from starting at all?
YES YES YES and ohh yeah YES
If you have a breather it must at least be in the opposite valve cover as the PCV, I suggest not having a breather at all with a PCV.
You need to take some time and think about what the PCV (Positive Crankcase Ventalation) does. It connects the vacuum of the intake manifold to the valve cover, which in turn connects to the crankcase, and the other valve cover. This is done so that the blowby gasses that all engines have are sucked into the intake and burned in the cylinder, this is a good thing. It also helps seal the engine from oil leaks and the rings.
So think thru these 2 questions; 1) What happens if the breather is in the same valve cover as the PCV? 2) What happens when there is no breather, just a PCV?
As for it effecting how it runs, well where does the engine get it's air and how does the vacuum leak of the PCV effect that? This isn't terribly complicated stuff. If the air source of the PCV is gone there is less are going into the engine, this has the same effect as closing the throttle.
My suggestion, hook up the PCV, plug the breathers, and go at the carb with a screwdriver and tune it.