Getting a distributor in the right position in a MGA

[RatiganJ@aol.com]

Fellow listers...

     I am replacing my distributor on my 58 MGA 1500 after an engine rebuild.
 All of the manuals (the shop manual, A-Antics, John Twist's book) talk about
positioning the distributor drive gear with "the large offset uppermost".
  Now, the distributor drive gear appears to my eye to be symetrically with
respect to the slot for the distributor.  Am I missing something in this
"large offset uppermost" instruction or are my eyes really that bad?

     Thanks for your help.

     Joe Ratigan