I've said before, I'm relatively new to the details of overhead valve engines and the y block so be tolerant with me please. I have this 272, supposedly rebuilt, that is using a quart of oil every few hundred miles. The left side tail pipe is burning clean, the right side is oily. I pulled the plugs and #1 is the only one not clean. Recently I headed the car down a steep embankment to turn around and a puff of blue smoke blew past me from the right side exhaust. I pulled the valve covers and ran the engine to check for anything unusual. At idle, the right side rocker assembly is putting a lot of oil onto the head in the center and filling up the valley at the bottom of the head before it can drain out. The drain at the end of the rocker shaft is clear and draining oil. I just pulled the right side rocker assembly to check for wear in the shaft or rockers that would let too much oil out before it makes it to the end drain. Obviously they weren't replaced at overhaul. I found wear, but not as much as I expected to find. Using my Harbor Freight digital calipers, there seems to be about .003-.004 wear at the rocker locations compared to the other unused portion. I can just catch it with my finger nail. I haven't pulled the assembly apart to check for rocker wear, but I can't wiggle them on the good part of the shaft, maybe because of the spring pressure. 

I know it is good that the rockers are oiling that well, but excess needs to go the the end drain. My question is: Does this amount of wear sound like enough to overwhelm the head drains and allow the oil to flood the valve stems? The engine internals appears clean as a you would expect from a rebuilt engine, absolutely no sludge. I see the shafts are available and not that expensive and would change them in a heartbeat if it would minimize oil escape. I would appreciate you sharing your valuable knowledge and experience. 

Just a few things I wonder about how many miles on the newly rebuild engine could be your high oil consumption could be because nothing has really seated. Also the down hill puff of smoke is usually a sign of bad valve seals they could be dry or installed improperly slight puddle in of the oil should be ok but I guess if there is to much oil it could overwhelm the seals. I am no expert but it's quite possible your engine was rebuilt but the heads were not and you may have excessive wear on the valve stems and no material what condition of the seal you are going to suck oil down in the intake stroke . I do not think rocker shafts are the issue . Just some thoughts

You could very well be correct about the heads. This car showed 82,000 miles on the odometer at the time it was rebuilt from a very weathered Arizona car. I just pulled the left side rocker assy and it is hardly worn under the rockers. Upon looking closely at the oiling holes in the shafts and arms, I see several that are packed with hard crud. They were still oiling some because I see oil accumulated on the valve retainers. I think they just got washed in a parts washer and reinstalled, and maybe the heads, too. The stem seals are there and look good from what I can see through the springs.

Anyway, I've decided to replace the shaft on the right side and clean up the rest of the parts and the complete left side assembly. That needs doing anyway. I'll run the car for a while and monitor it. Maybe will wind up pulling the heads to be rebuilt

Looks like you did a nice job on the car , I think after what you have said the valve stems are worn

I didn't build the car. I had sold a '40 coupe that I did build as a street rod and drove all over the southeast for 20 years. The builder of the '55 did a good job cosmetically, but sorted or adjusted nothing. I knew some of it before I bought the car, but found a lot more afterward. 

You may not have noticed, but did the arched metal tube on the end of the rocker assembly dump into the pushrod hole at the end of the head?  That tube ensures that the rocker shaft stays full and the excess comes out of the tube.  If the tube dumps onto the head surface, the drain holes may be overwhelmed and oil rises in the valve cover area and floods the guides.  Also be sure the small drain holes at the front and rear of the head are clear.

John - "The Hoosier Hurricane"

The tubes are pointing into the push rod hole. This engine has the little catch pans under the rocker stands. It is evident that most of the oil is draining into the center two pans and onto the heads. From the condition of the heads and rockers, I believe a half-a$$ed rebuild was done on the engine. It might not have even been bored, just bearings and rings installed. In the end, I'll probably have to go through it again. It does have good oil pressure though. 

When I rebuilt my 292 I had the new Camshaft oil Groove machined to I think .019 which is the recommended Groove Depth. As a result I got good oil Flow to the Heads. Too much actually. I had to tap the oil Feed Hole in the Rocker Stand and install a restricter to cut down the flow to the Shafts. If You are getting too much oil to the One side you could do the same. A small  Pipe plug with a hole drilled will cut down the Flow. The Rocker Shaft Stand is easy to Tap. Soft Metal. Have You done a Compression Test to get an Idea of what kind of Shape the Engine is internally? If You have even One low Cylinder that could be where the Oil is being burned.

  

No, I haven't done a compression check. I know I should have already but I don't relish it with the plugs so hard to reach. I'll do it while I'm dealing with the rocker shafts.

I just re-read your original Post. If You have One only oiled Plug as You indicated that would be the Cylinder to check Compression on. If You have the type of Compression Gauge that screws into the Plug Hole testing is not that difficult. If only One Plug is oiled possibly there is a broken Oil Ring or One not properly installed with the Expander not keeping tension on the Rings. Or it might just be the Valve stem Seals not installed properly or split if they were not replaced. If you only getting Oil Smoke from One side that at least gives You an Indication of which side the problem is on.