The coolant holes in the head may be drilled at a 12-degre angle, as discussed in this
thread. This could cause them to appear slightly wider or non-circular.
I may be wrong, but as long as the holes in the head are not so poorly made that they do not line-up with the holes in the gasket, and that they don't leak, you should be ok. When I was young and ignorant back in 1958 when I built-up my first 261 back in 1958, I was not even aware of the steam holes and I just bolted my 848 head on without drilling the holes. As long as I was running a fan there was not an over-heating proble, and the block did not appear to have suffered any damage.
