. . . I'm not sure how many miles are on this thing OD says 89,000 but could be a 189?
If you are referring to the number of miles on the engine since the last rebuild (with the odometer showing unaltered mileage and the engine never having been rebuilt), would a 1965 engine go 189K with a rebuild?
I know nothing about mid-60s and later engines, but I doubt if a mid-50s and earlier engine have gone 189K or more without a rebuild.