I know this is a fairly old thread, but I have a similar question about connecting from a BA flight (LHR-YYZ on 777) to the LA flight (YYZ-JFK). I'm looking at flying this route in February in J and was wondering if I have a chance to make a 90 minute connection, or if I'm better off just planning a one-night stopover in YYZ. (I'm a US citizen and I'm planning on taking 1 piece of checked luggage.) Thanks!