If the code cannot be found, then identification can also be made by looking at the case measurement from front to back, not including the bell housing or rear pump section.
MEDIUM CASE = 10 1/4" Case Length (1955-1972)
PAN - 1956-1957 Lincoln, Mercury 368
PAW - 1956 Ford, Mercury 312
PBA - 1957 Ford, Mercury 312
PBL - 1958-1960 Ford, Mercury, Edsel 352, 361, 383
PCE - 1961-1962 Ford, Mercury 390
PMB - 1955 Ford, Mercury 292
PMC - 1955 Lincoln 341
PME - 1956 Ford 312