Technically, it is enough time. However.... I deal with numerous people on a daily basis who book such connections and then either get angry or upset that our service is running 10-15 minutes late which means that they are getting closer to missing their connection. If you are sat neat the back of the 767 or an A321, which frequently operate the FCO services, even when the door is open, it can easily be another 5, 6, 7 minutes before you get near the door...

Personally. I would NEVER book a connection like this.

You will have to go through the flight connections centre and then through security again, all of which take time. So, even if you have your IAH boarding card scanned within the minimum 35 minutes before departure time frame, you may still find yourself running through the terminal to make your IAH flight...

If you choose to do it, then best of luck, but you are taking a risk.

Of course, it could all work a dream, your FCO be early and you end up having plenty of time, but that is not likely.

Regards,