How much time should be budgeted for a transit such as below:

2 separate tickets, both BA
ZRH-LHR connecting to LHR-JFK in F. Will have checked luggage, so will need to pick that up and recheck it. How much of a connection is sufficient? My options are a 3hr connection or 5hr connection. Leaning towards the 5hr just in case of a delay on the earlier flight. Only thing is the later flight is on a 789, I would prefer the 777 F.