Re: Oil plug and oil fill questions
Its for the PCV system, it draws contaminated air out of the top end of the engine, and is only needed on one side, as vacuum is vacuum all enclosed in the engine. Only time you MIGHT see 2 hoses (one on each side) is for drag / racing cars, and its not a PCV system in the sense that they are designed, its an evacuation system that the hoses are hooked to the exhaust system on each side. (in the header collector) Causing a "draw" of the air out of the engine.
Cheap, Fast, Reliable... Pick 2...
'70 Mach1 351C 4v 4sp 4:56's Been abused sense '79, needing tlc
'61 Fairlane 500 292 2v Cruise-o-Matic also needing tlc