Core Shift. Not sure if TR's had the issue, but it can limit (or increase) amount of bore.
Machine shops can check through water ports to outside on cylinder walls from bore surface.
One of the engine designs I work on can go 180 with no core shift.
Oddly, some of the ones I have worked on came factory sleeved. Knock worn sleeves out and none, it's .o83" over, and they make (made?) pistons and rings that were.....083" over.
Longevity-wise for you, if it takes more than .020 to clean it up, finding slugs bigger without using Egge Machine (if they're still around) may be a trip.
My Jag was .040 over, had broken rings, slugs okay, power honed okay....but nobody had .040 rings for it. Did .060 rings, gapped the ends, runs fine.