Quote: The discharge passage is only 0.5" dia from the factory, but the block can be 9/16 to 5/8". So I drill it to 9/16" dia, but not all the way to the o-ring groove. There isn't enough room, so I blended it there.
I do all the tricks too but... I go all the way through the pump housing.. I still have metal for the inner boss but it is very thin. I replace the o-ring with a rubber gasket. I get the gaskets from ACE Hardware.
