While the head is off, take a long, thin rod and poke around through the coolant passages to the bottom of the block and stir up the sediment as much as possible. Then install the head and back-flush the block through the drain petcock hole. Sometimes a thick layer of rust and crud accumulates around the bottom of the cylinders that no amount of in-the-vehicle flushing will dislodge- - - -it takes several hours with the bare block in a power washer cabinet with a strong, hot cleaning solution to clean it out. Good luck!
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!