I have a 55  272  with a problem of #8 cylinder pumping out enough oil to run out the manifold to exhaust flange   I have made a few changes and honestly dont know if either has affected the problem  and dont recall which came first.  I installed a 4 barrell set up with a t pot carb , at the same time removed the valley pan and built a baffle and hole to install a pcv  Again I dont really remember this issue before  but my memory is not the greatest . with the amount of oil involved I was sure there was a breach in the head gasket between # 8 and the oil return hole in the..  block , very close proximety . A very good friend and retired engine builder  has suggested  rings in that cylinder  , it had best compression of all 8.  but I didnt believe that much oil could be from rings on that one cylinder with good compression  Well I pulled the head off and much to my dismay found no breach in  head gasket  . my friend came over for a look and confirmed no gasket damage , all oil seals were in place and valve guides were good . So he pointed back to rings.  I just hate the job of pulling the pan  , ive done it before and have to jack the engine up and various other things .. I guess what I'm asking is does anyone have any great ideas as to  what  else   if anything could be going on or a similar situation   thanks in advance  Fred  at 76  its a bit harder than 20 years ago LOL

Where are you pulling the vacuum for the PCV valve from?  What’s the casting number of the intake manifold you are using?

Lorena, Texas (South of Waco)

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Thanks Ted for your response.. casting # is ECZ-9425-A  vacuum source is at the rear base of T pot carb  there seems to be no oil in the intake runners from the pcv

thanks Kultulz interesting .. not sure how that would get oil into the intake didnt look like any leakage from bolt head to port .. thanks Fred

If the cylinder head was still on the engine, I would suggest performing a leak down test on that particular cylinder.  From the amount of oil you describe, broken piston rings are a strong possibility.  Something else to look for would be a hole in one of the pushrod holes within the cylinder head for the #8 cylinder which would be allowing oil to suck directly into the intake port and then into the combustion chamber.

Lorena, Texas (South of Waco)

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plug is oily

Valve guide seal

valve seal and guides are good  thanks Fred