These mills usually use a metric frame motor. So you have some options:
Check your dimensions against this chart - it seems to me this is a IEC 71 frame motor..http://www.electricmotorservice.net/iechart.pdf
Then find a supplier locally or out on the web. I got a 3 phase chinese motor for my mill when I ordered it from MTW (in Canada like you..) https://www.machinetoolswarehouse.co...log/index.html - I personally think this is fine as the problem with most of the Chinese motors is in the start circuit and capacitors which 3 phase motors don't have. Saved a bunch of money doing it that way too - US / EU / name brand motors cost a lot more but for my hobby machine I'm happy with what I bought.
BTW - I'm not affiliated with MTW in any way - just a customer who got what he ordered ( becoming a rare experience these days...)
Others have posted elsewhere here on the zone drawings for an adapter plate to the nema C face motors (in the IH forum I think) but in my opinion that is not the way to go when you need a motor - if you already own / have a motor then yes it makes sense but to add to the cost of a motor a machined adapter seems like an inefficient, kludged up way to go...I'm all about cheap BTW...
My 2 cents...