Good Afternoon,
Need a little help. Just acquired an 81 Bronco with a 351M in it. After pressure washing and working on it for a few days I got it running. Now I find a hole in the heads that is spewing a little oil. The hole is approx. 1/2" located about an inch below the top of the head on the intake side between 2,3 and 6,7 cylinders. The hole on the right side does not blow oil and appears closed off. The hole on the left side is the one blowing a little oil. Can anyone tell me should this hole be plugged? Did I blow some kind of breather filter out of it when I pressure washed? What is the hole for? Any help is appreciated. These are factory heads and factory intake manifold.
Thanks, Tim

 

Figured it out.

 

So, what was it?

 

Exhaust heat dissipation hole. Probably full of 35 years of blow-by and such. When I pressure washed it I think it got water in it. As the water and gunk boiled off it appeared to be oil coming out. I got some absorbents and soaked it out last night and it appears dry. At least that's the story I'm going with right now.