Had a '57 312 block magnafluxed, the shop uses wet fluorescent process. Shop told me that it was cracked at the three center main webs in the area of cam bearing feed, a picture of the locations that shop marked is attached.  Shop did say that they did not see anything on either cam or main bearing bores. I have not seen a Y-block show cracking at this location before, but have had many cracked at the main bearing bolt holes. Is this a this a problem area or is there something in the casting that may be causing these indications?  I also find it hard to believe that all three inner webs are cracked.  Does anyone have in-sight on what may be going on?