You mean Packard’s Straight 8’s?
I saw a Packard V12 once. Art. (At Peterson Museum in L.A.)
A well-tuned Packard straight-eight at idle speed, you could balance a nickel coin on its edge atop the engine head, and would simply stay upright, no jiggle or roll. Altogether a different piece of machinery than the V-12’s, which were also modified into aircraft engines.
That old Packard could tick over about 300 RPM, and be near whisper-quiet. In the Second World War, three of those V-12’s were used to power a PT boat, and when all three of them were running and engaged, well, that is why the PT boats gained their reputation for fast, top speed about 40 knots. The Packards were well respected.