It appears that Delta has found ways to strangle even some of the remaining non-ExpertFlyer sources of data about it, as one source where I have found MCTs in the past now shows "suppressed" for all MCT data relating to Delta.

That said, published generic MCT for EWR (and I would think for most US airports) is 90 minutes international->domestic, so I'm surprised you're able to book an 84-minute connection, even though I agree that in this case it doesn't seem terribly risky. If you are booking it as two separate tickets to get around an MCT restriction, you may run into trouble if something does happen to delay you on the first flight.