I think you should get a Manual
first. Try CBS above.
There is no hole opposite the sludge trap plug, maybe a countersink hole for grinding the rod journal. The bolt going through the flywheel holds the sludge trap, take that out first. A large EZ-out or tap can be used to grab the tube and pull it. Sometimes a hooked rod can be used to catch the bolt hole from the inside.
Use a micrometer on the rod journals and main to see if they are 1- within diameter tolerance, 2- tapered, 3- round.
You should have left the main bush in the case until you measured the bore and main diameter.