Those older systems do have a slight advantage over the VC in VC out systems. Do a few high rpm blasts and get the valve covers a bit full of oil, don't have to worry about ingesting oil or clogging the breather with oil. There are a lot more pushrod holes to the lifter valley than there are drain holes to the crank case. More likely to have more air just getting blown across the lifter valley than down the oil drains, through the oil, pan and up through the oil drains in the heads. Modern engines have several PCV passages built into the engine and covers to better evacuate vapors and provide fresh air. PCV systems in older vehicles sorta worked, but were lacking with single point entry and exit systems. Are you just looking for a cover for the 'ugliness' of the PCV valve? Spectre 4284 is a cover that uses the PCV valve as its base, very simple design. Gives the twin breather look while being a PCV system. It uses a standard 3/4" PCV valve and the cover just sits on it and has a nipple to attach the hose to. Have used them to eliminate the PCV 'ugly'. If you are good at fabricating you can modify one of two breathers and make it work if you are looking for a specific look.