Grease on a drill bit would capture most of the shavings. You could probably catch the rest of shavings by pulling the valve cover. Shove a rag with grease smeared on it right under the hole your drilling.
Also, put a shop towel down in the lifter valley to catch the chips. You may also go to the local hardware store and get a few bar magnets and place them on the shop towel under the hole while drilling, so the magnet catches most of the chips.
