Yesterday my '84 351w HO Bronco blew it's oil all over the freeway over about ten miles. Didn't sieze up fortunately. This happened I think because of an aftermarket crome breather cap that didn't flow enough air for the PCV system. The cap in question was dry when I took it off to add oil. Previously I had another type of aftermarket cap on it that was letting oil out all over the valve cover. I had replaced the PCV hose and a couple of days prior I had the EGR plate off to replace an EGR valve and none of the ports were carboned up. Most of the oil went out the rear of the intake and possibly the rear main and timing cover. It did have a slight rear intake oil leak before this I hadn't fixed yet. Oh, and the PCV valve was a new one from Fram per the book at the store and had vacuum when I held my thumb over it.

Do these engines need a massive amount of PCV airflow? Do I have an enormous amout of blowby? What happened?

 

Anyone have any sort of ideas? I'm stumped and don't know how to keep this from happening again. Should I post this in the Bronco section?