I'm just wondering if there are any advantages or disadvantages of running an Automatic Transmission car, with a 4 bbl cast iron intake manifold, (with the the PCV nipple in the front and two breathers from valve covers to the Air Filter). Would there be any difference over an automatic cast iron manifold with one breather from valve cover to air filter and PCV to one valve cover? I am not a mechanic so I don't know if there are any intricacies involved here.

Thanks for any input.

 

From an operational or performance perspective the intake manifolds are the same.