Morris Minor Owners Club

Some will shudder but I have an alloy rocker cover and it has no breather. I would like to fit it and so have sourced a 5/8inch UNF breather take off for a 1/2 inch hose.
Is it a relatively easy job to tap a hole drilled in the correct point of the cover where the casting has a circular, thicker area.
I have a simple pillar drill.
What drill would I need for the first hole which would then be tapped - will a hand held tap then be OK?
How would I ascertain threads per inch on the take off fitting?
Hope you can help

You take a chance - just make sure the fitting doesn't foul anything inside the cover when fitted. But you are correct to make sure you have a breather in that cover. You say it is 5/8" UNF fitting which is 18 TPI and the drill size is 37/64.