I use an inexpensive bronze rifle cleaning brush and a cordless drill to clean oil passages in blocks and crankshafts, along with brake cleaner spray. A 20 gauge shotgun brush works well for the large oil passages for hydraulic lifters. A 55 gallon oil drum filled with water and sodium hydroxide drain cleaner (lye) and a heavy dose of laundry detergent, works well for big parts- - - -blocks, heads, crankshafts, etc. Build a fire under the barrel and boil it for a few hours. Just don't put any aluminum parts like pistons, timing covers, etc. in there- - - -they'll disappear!
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!