My 422 smallblock build

I drill at an angle not parallel to the line bore
does not matter as long as you hit the oil passage coming down from the oil feed
most likely the passage to the cam bearings
clean out the chips with a wire brush or hone in the oil passage
I do not have a block handy to look at as I'm out of state

Ok if you did not bottom tap the threads square at the bottom drop a bb into the hole before threading the stud
if you torque the stud and you have a tapered tap thread you can split the web
the stock bolts are short enough not to be a problem
ask me how I know