I've seen that article before, and it would be a pretty simple setup job to get a piece of 3/4" steel plate surface-ground on both sides so it could bolt to the back of the block with the bellhousing bolt holes and support a cylinder boring bar. The cat's paws on the boring bar will center the cutter in the rear main bearing bore, and the boring cutter can be set to a series of diameters that will end up a few thousandths below the outside diameter of the one-piece seal. It would probably require somewhere from 6 to 8 passes with a square-ground tool to make the seal counterbore. Then the seal can be driven into place after the crankshaft is installed.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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