I know this is a much discussed issue, but I wanted to bring it up again as it is a constant headache for many, me included.
I am looking for insight, solutions, etc...
History:
I have an 81 that I have owned for a year now. I have done a good bit o work on the car to included the fuel system. New Fuel distro, steel braided fuel lines, new fuel pump, accumulator, and J Herveys fuel pump kit with his fuel pump. The Car had fuel pump issues before I owned it(records) and it had a J Hervey(JH) pump in it then. It also had the stock fuel pump kit in the tank. The tank is spotless, no contamination.
The car took a dump on me a few times and quickly figured the pump as the culprit. It would get hot(summer time in ABQ NM) and the pump would get louder and louder. Finally the car would start to buck and sputter till it would just die. So, I ( novice D owner) talked with JH and he said his kit was great so I bought it.
The car failed shortly thereafter(last summer). New Fuel pump( from JH) and cooler temps brought a a good driving car that is driven a few times a week.
I recently overhauled the entire cooling system. New, electric, fans for the radiator. water pump, silicon lines, etc..
Anyway, two weeks ago(high 80s) I was driving with 1/4 tank of gas and the F pump start to scream. I quickly found a gas station topped off and the sound was gone, back to normal. Last week, while driving in city traffic(90deg F, mid day) the car got just above 220deg and then the pump started to sputter again(3/4 tank of gas). I drove it another 7 miles before the car died. I had to let her cool off a few hours and she started right up.

Questions:
I am certain the issue is the fuel pump, but why? It is a JH pump and it worked well thru the winter, but AS SOON as it got hot again, she crapped out.
Both cooling fans are working well. Are they heating up the fuel tank? Does deflecting the air from the tank help? I want to fix this and hope y'all can help!
LASTLY, of those that have seen or own the new DMC pump/sender unit, what are your thoughts?
Is there a good fuel pump out there? How/where do you get it?
Thanks