The 340 is out....again.....

I've seen the holes partially drilled myself. As common practice (and it appears it is common practice for you as well) I drill all the feed holes to 9/32 just to make damn sure they are done. I have heard of, but never seen an oil feed hole not drilled at all, as in no oil hole at all. I'm sure that is possible, but it would seem that by this time, all that stuff would have been flushed out. Is it possible the OP's block was incorrectly drilled for all these years? I'm sure it is. Maybe he is making more power now, or using more RPM to make the issue show up.

It's always something that bites you in the ***. I'm sure the OP is double sick of it.