Before you go to the trouble of pulling the pan, try a Diesel fuel flush to dislodge the majority of the crud. Fill the engine with clean (cheap) oil, and then add 2-3 quarts of Diesel fuel, enough to let the crankshaft whip down into the oil. It will splash the solvent-added oil around like the agitator in a washing machine and do a better cleaning than you could ever do with a brush. Run the engine for 20-30 minutes at 1500 RPM or so, and don't put any driving load on it. Drain the oil while it's still hot, and most of the crud inside will also drain out. That procedure will also clean the valve lifter valley, the heads, and the valve covers, if you haven't given them a good scrubbing already.
Jerry
