“Hand fit, but only once“, and “never again”” while the Packards were “built to tenths, and everything still fits,” (80 Years later) engine to engine, part to part.
That continued with the British automobile engines until the mid fifties. The cylinder block would have stamps on it showing 010/015/020 on each bore showing what oversize piston rings to fit. The crankshaft would also have the same treatment.
Working on American engines you just dropped in the correct part number.