We probably won't ever agree on the best stock inline six (I’ve hear the knight sleeve valve was really smooth) but I wonder which was produced the longest? I know Mopar built their flat-head from the start (1924) until the late sixties.
Anyone know a longer one?

By the way I looking at a 1957 Fire truck last week that had a 935 CI Hall-Scott overhead cam 6 in it. 250 HP at 1800 RPM! The same engine was produced by Hudson for marine use.

Leif in San Rafael (I got a new job and I'm not in Oakland anymore)