66 Rearend Number Question

[Kenneth A.]

I found the rear axle number on my 66 Coupe. It is AU 41266. I understand that the AU means 3.36 ratio, the 4 means april, the 12 means the day and the 66 means 1966. The problem is that the book I have shows that the plant code should be at the end not the year. the example in the book is AK0621W with the W being the Warren plant. Can anybody help me understand this. Thanks

[R N.]

Re: 66 Rearend Number Question

My '66 rear end is stamped FA 31666, no other numbers.