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Old 10-28-2022, 12:20 PM   #1
wazzabie
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Delco 10si alternator date codes

Did Delco skip a letter in the date code? i.e. 7L12 Would this be 1977 Dec 12

a - Jan
b - Feb
c - Mar
d - April
... ?
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Old 10-28-2022, 12:32 PM   #2
MJN
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Re: Delco 10si alternator date codes

In my book it shows L as November, 'I' was usually skipped as it could be confused with the number '1'.
7L12 could be
7= 1967, 1977, 1987 (they didn't indicate what decade)
L= November
12= 12th day of November

A=Jan
B= Feb
C= Mar
D= Apr
E= May
F= June
G= July
H= August
J=Sept
K=Oct
L=Nov
M= Dec
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Old 11-12-2022, 04:23 PM   #3
wazzabie
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Re: Delco 10si alternator date codes

To make the alternator "numbers matching" how close should the alternator be to the build date of the vehicle?
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Old 11-13-2022, 08:51 AM   #4
Dead Parrot
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Re: Delco 10si alternator date codes

One thing to watch if you are recreating a 'proper' alternator for a vehicle is that the output amps were often stamped into the outer case. For example, 63A for an alt with max output of 63 amps. Check the SPID for what alt the vehicle came with and match the output stamp as well.

Not really sure on the normal lag between mfg and installation in a vehicle for alternators.
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