/// Another Bunch Of 273 Commando Rebuild Questions? ///

What is the goal of the build? Just a rering /bearing and seal or a rebuild? What block machining is planned if any? Do you have a bottle brush kit? If it were me, and because it is apart and an “unknown” Depending on how the cam bearings looked. If they need replacement I would remove all the plugs in the block and have it cleaned professionally. Then when you get it back scrub it with bottle brushes. Then scrub it again…..then again. You will need to dingle ball hone the cylinders at least if they are straight and round. Nothing wrong with using a dingleball hone for what it is designed to do. Give you the correct surface finish NOT the correct bore size or geometry. After that take a rag with ATF on it and wipe the bores and see if the rag comes out clean. ATF has serious detergents in it. If the bores are glazed you really need to break the glaze to get the new rings to seal if boring the block is not in the cards or needed. Things really can’t be too clean.