Contacting some of the small volume cam grinders could potentially find you a large journal cam although it may not be a stocker.  Here are some links to get you started.
http://www.oregoncamshaft.com/classic-car.html
http://schneidercams.com/
http://www.nielsoncams.com/
 
To fix the cam tunnels in some of the 312’s, the cam bores are being enlarged to the 1954 cam bore size and new cam bearings are being made from bearing brass.  While this fix is good for correcting cam tunnel alignment issues in the 312 blocks, using these same machined bearings would permit the later model cams to be used in the 1954 239 & 256 Ford and Mercury engines.  The distributor, oil pump, and oil drive would have to be upgraded accordingly to allow a matchup to the 1955 and up distributor gear on the camshaft.
 
When giving the dimensions to your local machine shop for the new cam bearings, be sure to include an increase in oil clearance for the cam shaft simply due to bearing brass having a different expansion rate versus that of babbit.  I’ve found 0.006” oil clearance with brass to be sufficient versus 0.003” for babbit material.

Lorena, Texas (South of Waco)

Are you looking for new or used? I saved my old one when we rebuilt the motor. New might be a problem.

  Dennis in Lititz PA

Looking for a 1954 2.500 journal diameter Ford/Mercury 239/256 Y block camshaft. This is a one-year only cam for the 13 tooth distributor gear. Later cams were the smaller 1.926 journal diameter for the 14 tooth distributor gear.
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