If you can't eyeball the edge distance of the existing hole and tell if it's a candidate for increasing the bore...

All my blocks are drilled with a hand-held drill and the correct tap, even the mundane daily driver blocks. I drill 'em all the way to the intersection and then use a rotary burr to smooth out the sharp corner. (easier with the larger hole)

I figure I gotta get a new pickup anyway and the 1/2" price isn't that bad when included in a complete overhaul.