Flushing a Slant 6

JMO, I would put the engine back in and and add new fluids and filter and fire it back up, drive it and change the oil and filter after ... ah.. 4 hours of driving.
Cost would be about $15.00 and you will be assured that the cam and crank bearings did not have to wait for oil because you flushed the engine with something .. Just me, and I am in no way a good tech here, just worried about a dry start or putting anything in the engine that does not belong I guess.