[Mr.Fixit]

Most shops use a recirculation recollection device that you don't have. If the old days, we would just leave the petcock open, radiator cap off, run the motor and keep topping it off with the garden hose until all fluid coming out is clear, but we shouldn't do that now that we know better. On the motors we did, we always put drain petcocks on the block instead of pipe plugs. You can pressurize the water system with air to try and blow most of the remaining water out the lower hose, this has worked for me before I pull a motor out so as not to make a huge mess. Just remove a fitting from the top front of the intake and connect there.