Hemi Continues to quit at Speed.

Good advice here. I agree with what everyone is saying, just wanted to add that there is lots of reports of new aftermarket crank sensors failing, mopars like oem sensors.Wasn't sure what you are using.
Also I have heard of coil packs shorting out on secondary side and if there is no ground straps on valve covers can cause problems with stalling out from 5 volt side of pcm shutting down from high voltage spikes .
Lots of problems with egr valves on the hemi engines with them causing a stall , but that's on a stopping situation.
Also you can use a heat gun on the suspected sensor,pcm etc. to get hot and get the problem to show up.