A running engine flush will clean out a lot more sludge than a manual scrubbing- - - -no need to remove the pan unless you're planning to fix a leaky pan gasket at the same time. Overfill the engine with Kerosene or Diesel fuel- - - -3 quarts or so added to a full fill of oil, and run the engine at a fast idle for 20-30 minutes- - - -about 1500 RPM or so. DO NOT DRIVE THE VEHICLE OR PUT ANY LOAD ON THE ENGINE! Drain the oil/solvent mix while it's hot, and virtually all the sludge will go with it. The crankshaft and connecting rods dipping down into the high liquid level will splash it around like the agitator in a washing machine.

A 235 has a pickup bolted to one of the main bearing caps, with a tube from it to the pump. You can remove the pickup screen and tube by simply unbolting it and disconnecting the line from the pump. I have fabricated a new strainer screen to replace a rusted or damaged one from fine mesh stainless steel screen available on Ebay Just fold the screen into the right shape and pop rivet it to the sheet metal pickup housing.
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!