Decoding '55-'56 Powerglides - NCRS Discussion Boards

Decoding '55-'56 Powerglides

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Michael H.
    Very Frequent User
    • December 1, 2004
    • 118

    Decoding '55-'56 Powerglides

    How does one distinguish between a 1955 and a 1956 Powerglide transmission? A friend advises me that, based on information contained in Corvette by the Numbers, the identification code on a '55 is identical to the id code on a '56 (i.e., 3708188). Also, I understand that the portion of the '53 to '55 NCRS Judging Manual (page 62) describing the date code for a '55 Powerglide is virtually identical to the corresponding description of the date code for a '56 as contained in the '56 to '57 JM. Specifically, both JMs state that the date code begins with a "C" (for Cleveland), followed by one or two digits for the month (1 to 12), followed by two digits for the day of the month (01 to 31), followed by "D" for day shift or "N" for night shift (which obviously means there must be a minimum of 3 digits in this alphanumeric code).

    If the id number for both a '55 and a '56 Powerglide is the same, and if there is no reference in the date code of either to the "year" (but rather simply the month and day), how are the two Powerglides distinguishable? Also, has anyone heard of a date code for such transmissions that contains only two digits (versus 3 or 4) following the "C" and if so, what does this mean? Thanks,

    Mike H.
  • Roy B.
    Expired
    • February 1, 1975
    • 7044

    #2
    Re: Decoding '55-'56 Powerglides

    The main case and bell housing 55 to 57 all use the same CASTING numbers , the tail housing is different then a 55. Only the clutch's are different in a 55 then a 56 to 57. The clutch's in a 55 have square teeth and 56 up have fine teeth , so when ordering a rebuilt kit you need to know what year your working on.Besides that you need to read the date code. 58 again is different having the added modulator R/S

    Comment

    • Michael H.
      Very Frequent User
      • December 1, 2004
      • 118

      #3
      Re: Decoding '55-'56 Powerglides

      Roy,

      Any idea why there might be two digits following the "C" in the date code, versus at least three (and possibly four) digits per the NCRS Judging Manual? Thanks again.

      Mike

      Comment

      Working...

      Debug Information

      Searching...Please wait.
      An unexpected error was returned: 'Your submission could not be processed because you have logged in since the previous page was loaded.

      Please push the back button and reload the previous window.'
      An unexpected error was returned: 'Your submission could not be processed because the token has expired.

      Please push the back button and reload the previous window.'
      An internal error has occurred and the module cannot be displayed.
      There are no results that meet this criteria.
      Search Result for "|||"