I am connecting in Dallas to get to Heathrow. For my connecting flight in Dallas, should I expect additional security/customs procedures before boarding the flight to Heathrow? I only have an hour and 10 minutes between flights.
I had the same flight last month and we did not have any additional security or customs until we got to LHR.
No, you'll be fine. No extra security or customs procedures to go through. Depending on what airline you travel on, the most you'll have to do is change terminals - which is done easily inside the security area by tram - and is easily done in the time you have.
We always connect at DFW coming from Tulsa and then fly to LHR. There are no additional security checks at Dallas. You should have no problem if your arrival flight is on time.
DFW is my home airport. Changing terminals is easy. Look for the "Skylink" sign. You follow the sign to a long escalator which goes up top to the station. Once at the top, just look for the sign for the terminal you need. It is easy and fast. If you look at the departure screen before you go up to the Skylink and find your gate, you can get off really close to your gate. Each terminal has about 3 stops I think.
Oh, I just noticed you are from Abilene. I probably didn't tell you a thing you didn't already know about Dallas. :)