Unless you remove the block drain plug(s), you won't get all the water out, so mix the coolant a little strong on antifreeze when you refill the system. A stovebolt six has a block drain on the driver's side near the back, and the V-8's have one on each side, centered in the block just above the oil pan rail. You might have to poke a wire into the hole in the block to clear the sediment away if the block hasn't been detail-cleaned recently.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!