I'd suggest Sonic Test it, and then post the results here if you can, it would help the rest of us too.
The cost of a Sonic Test $10-$15 per hole) is pretty small compared to boring, pistons, bearings, etc - a whole rebuild.
80-over vs. 60-over is only 10 mils thinner cylinder walls - I can never see the logic of a firm yes or no in there until it is sonic tested.
Even then - what is the minimum thickness you will gamble on - depends on the use.
I've never regretted sonic checking, strongly suggest doing it before putting any $$$ into the buildup.
