There were two 239's, one cast in DEARBORN (DIF) and the other in CLEVELAND (CF).
The DIF 239 was the oddball engine and saw assembly in the PASS CAR. The CF 239 was a different design, forerunner of the 272-292.and was used in LT. The 256 was used in PI, MERC (both 1954) and LT and HT (1954-1955). The 272 was introduced in 1955 as a running change, although cataloging shows it as 1956.
There is where the confusion is.
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