[legenmetals]

I think what JHV48 was referring to is what they call a closed loop system. That is a pcv valve that vents the internal engine vapors to the base of the carb to burn any vapors off. Cars in the mid to late 60's had a breather on the opposite valve cover that did not have the vent holes underneath the breather cap but a sealed cap except for a hose that attached to the cap that vented in to the air breather to suck any vapors into the carb and not the atmosphere.