That sort of connection would have 2 rounds of security in Dublin and 2 rounds of passport checks, the first one to typically establish that there isn't a passport check for entering Ireland, the second to establish bona fides for the USA. The robots would fix this mis-connect to give a 2 hour connection. I would certainly be researching alternative options at this point, bearing in mind the OP holds a LHR to MCO ticket. Other routes may be easier.