Originally Posted By John_Kunkel
Originally Posted By Cab_Burge
Are you a machinest? I'm not


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.



I do it the same way,
except I first use a die grinder to remove the threads 180* opposite the thin side. This moves the drill center point over, leaving more material at the thin area and reducing the chance of cracking.
Another advantage with 1/2", it takes less power to turn the pump.