Hello Farmboy,
The Dack's do not have their size indicated on them or in the serial number so I measured the shoe.
http://kitsilano-kittys-closet.myshopify.com/collections/home-page-advantage/products/mens-shoes-vintage-dacks
They measure 11" on the inside. 4.25" across the widest point of the sole. This matches a US/Cdn men's Size 11.
The chart I used is here: http://shoes.about.com/od/fitcomfort/a/men_inches.htm
If that isn't your size, I am prepping three more pairs for the website - black Sherritt's, white tasseled loafers (1984 Anniversary), and tan slip-ons.
Best wishes,
Vlassis