How much cooking time should I allow for a 5 lb corned beef that I'm cooking in a foil-covered roasting pan (instead of 2.5 lb, dutch oven as call...

I have not made that recipe, but I am cooking corned beefs (4-5 lb) 3 1/2-4 1/2 hours til tender....just put a fork in it and if it slides in and out really easy, it is done....I don't think it should be any different because you are using a different container.