[blucar]

One item that many people overlook on the Y-Blocks is the crankcase breather on the lower left front of the engine.
Not all of the Y-Blocks had this breather, usually they were more common on the truck engines, 272/292 through '62. In many cases there was no breather canister, a flat plate was bolted over the opening. It has been my experience that the '63 and later 292's did not have an opening in lower left side of the block.
I currently have two '59 F100's in my 'stable', both of which are 4x's. I also have a '63 F100 4x w/292.

I have converted the '59 F-100's to the '63-64 PCV system, in lieu of removing the lower crankcase breather can I installed a block off plate between the can and the block, that way the engine appears to be stock, and the PCV system works like it should.
Throughout the years, I'm talking back to the early '70's I have found that the addition of a properly functioning PCV system on the Y-Blocks and pre '63 SBC's pretty well eliminates oil seepage from an engine due to the fact that crankcase pressure is eleminated.
The one thing that you have to make sure of when you add a PCV to an engine that did not come with one is that the port where the PCV is installed, be it a valley cover or a valve cover MUST HAVE A BAFFLE, without a baffle prior to the PCV the vacuum will suck oil into the line, causing oil consumption.
I would be very suspect of a rubber grommet in the valley cover being used with a PCV plugged into it and no provisions for a baffle.