The following technical article regarding 1963-1966 Tbird drums was posted in the September-October 1991 VTCI Scoop, Page 10. It was written by Bob Gadra, who at that time was VTCI President. Bob passed away a couple of years ago, according to his widow. She has given me permission to use his articles after I explained to her that I was retrieving older VTCI technical articles and maintaining them as an online edition. Here’s another great article from the members of the Vintage Thunderbird Club International, Inc.

I came across an interesting little article in the Tech Tips section in the September 1991 issue of Cars and Parts magazine. It was sent in by Dennis R. Kohn, headlined, Junk Drums? Check Again!
"Warning! Check your shop manuals before sending your drums down to the local machine shop for turning or the drums may be mistakenly classified as unusable." SO I DID!
My 1966 Shop manual indicates the read drum inside diameter as 11.030, drum maximum boring limit 11.090.
This is erroneous. The Ford parts and accessories catalog list them as 11.00, but under the description column they are specified as 11.090. I also came across Tech Service Bulletin 1910 Brake Drum Specifications for 1963 Galaxie and Thunderbird correcting the 1963 Thunderbird Shop Manual Section 13 Page 59. For 1963 and up Brake drum inside diameter is 11.090, maximum boring limit is 11.150. This applies to all drums front and rear from 1963 thru 1966. I have a dozen 1966 rear drums and almost threw them out because I thought they were oversize at 11.090. Live and learn.