I have two sets of NOS cam bearings for my engine to choose from.
The camshaft is a Howards with .515" lift springs, will be 280 lbs open pressure
The sets are #1 NOS Clevite 77   SH 559S      set #2 is old NOS Durabond F9a 
I plan on grooving the block cam journal like Ted Eaton has shown
Is one set preferred over the other?
THANKS! 

Of the two sets of bearings you mention, I would go with the Clevite set.
 
Without a production date on the bearings, it will be difficult to determine when and where the bearings were manufactured.  While a knife can be used to ‘test’ the cam bearing babbit for hardness, you do need an older reference bearing to gage that hardness.  The Engine Tech CC508 cam bearings for the Y are made in South America and are a much harder bearing than what is currently available from Sealed Power or Durabond for the Ford Y.  Those are a good alternative to the current crop of softer cam bearings.
 
Here are some options for reducing center cam bearing issues.

1. Adding a groove to the center cam hole in the block.
2.  Machining the existing groove deeper on the center journal
3. Grooving the O.D. of the center cam bearing with an oil groove.

 
While #3 is an option, the bearing will be weakened at its center and prone to buckling when installing it in the block using the hammer and puck method.  If installing that bearing with a screw type of cam bearing installer, it works. 
 
Any of these modifications will compensate for wear and flattening out of the center bearing when they are made with the softer babbit.

Lorena, Texas (South of Waco)

Thanks Ted!
I knew you would give me the right advice!