which common block modifications do you do/know and consider worth doing? what do you think about the mods listed below?

Things I came across are:

.) chamfer bolt holes on deck
.) break/chamfer edge at the bottom of each cylinder
.) groove cam bearing holes to 12 o' clock (--> clock cam bearing oil hole to 12 o'clock for a better oil wedge)
.) drill hole in thrust main oil passage (from rear) to oil thrust bearing (also drill bearing)
.) bottom tap all bolt holes