Not just a problem with seasoned blocks, my new MP block had the same problem,
The very experienced machinist insisted I bring a used cam with, to check the fit when the new bearings were installed and it was too tight..
a few minutes with a machinists knife and all was good...

A friend found out the hard way that a too tight cam is not going to fly, after he broke the dowel pin in the cam shaft try to turn the motor over after his machine shop guy machined the block, and installed cam bearings..