Crankcase ventilation, open or closed system?

As of now, i'm in the middle of my camshaft change on my sbc. I would like to set up a pcv system on my truck mostly to effectively ventilate my motor while keeping my valve covers clean and oil-free.

With that said, I've come across a diagram that Hamber C9 posted, but couldn't find any clarification as to which system would be right for me. I'm running a 70's 350 sbc with a mild cam (installing right now), dual plane intake, headers, and a holley 600cfm carb...very timid to say the least. I'm not sure if i should be running a "closed" or "open" PCV system, i do know, that i want to keep the outside of my motor clean, so with that said, it almost looks like a closed system would be ideal. But any additional insight would be great!

heres the diagram i was referring to:

 

The closed system is more effective at maintaining a slight vacuum in the engine and is more able to purge the blow-by.

 

If you are concerned about piston ring/cylinder life it's a good idea to use the lower sketch for a model but tap into the air cleaner in the filtered area so the low pressure of the crankcase (at cruise rpm) won't pull unfiltered air into the crankcase. Use real PCV hose, fuel line or the like will collapse in time and cause positive pressure in the crankcase, that can result in all kinds of silly **** like blowing oil out the dipstick tube and taking out crank seals.