[FFR428]

427craze, The marine blocks were all cast as sideoilers but drilled topoilers. If you look at the sideoiler casting hump you should see NO allen screws where the sideoilers are drilled and tapped. I also believe you cannot drill SOME of them as sideoilers because the marine motor mounts interfered with the sideoiler galley casting and were shaved slightlty for fitment. Was this common to all marine blocks? who knows?? Chances are if it is a service block the galley would not be shaved and you could drill it. You would get a fresh casting not modified. My guess that only factory installed (chris craft) engines would be shaved for the motor mounts. Either Dove or Gessford (or both) I think have drilled some but it is a hit or miss deal. I would run it as is or look for a sideoiler casting that is out of a car or automotive serivce block that has been drilled by Ford at the factory if your heart and wallet are set on it. So take a look and let us know what you see!Good luck, Glenn.