E118 = May 11, 1968

Tube numbers should be in the following format:

XXXXXX XX
X



The first set of two in the six place holder set, are the application code.
The second set of two in the six place holder set are, the two digit month.
The third set of two in the six place holder set are, the two digit day.

The next set of two are the factory and shift codes that are represented by single digits.

The last and lower most digit, represents the differential manufacturer code.

For more information, RearAxleNumbers and more information are provided.

The numbers you have provided just dont seem to make any F-body sense....