Due to the Midwest waiver & where I live getting 7 inches of snow this aft & ice & me arriving around midnight & then having to drive 35 miles through it when I'll be tired & on UK time, I've switched my return from LHR to oh-dawn-hundred tomorrow (LHR-IAD-ORD-GRR)

The agent was leery of putting me on the first connection to ORD after landing in US, so put me on the other one. But if I take that I get the last row of an Embraer 145 , but if I take the earlier flight I get a A320.

So if the flight from LHR leaves on time I'd arrive 11:10am to Dulles. I'm currently on the 2:45pm to ORD, but I'd like to switch to the 12:27pm.

Is 11:10am-12:27pm (1hr;20min) enough time to clear customs @ IAD & make next flight? I will have checked bags, but it's usually on the belt by the time I clear customs. I'll be in business class.

I haven't checked in for tomorrow's flights yet because I figure I'll need LHR to switch me to the earlier flights & it's probably easier if they don't have to uncheck me. But if you say it's not doable @ IAD, then I might check in so I get the extra few minutes of sleep.

Any input appreciated.

Cheers.