Here is a pic of my old 9.600" deck R3 bored 4.245". There would have been no issue with steam holes at this bore as they start from a 4 O'clock position and are angled 45 degrees from the deck surface entering the water jacket.

The issue with this block if had had steam holes "may" have been when repairing the block with sleeves. This block had two next to each other on #6 and #8 that worked well.

Leon