Well its possible you could be getting a partial vapor lock. They dont always completely cut off your fuel supply. Have you checked your fuel line under the car to the tank to see if your exhaust is running anywhere close to it or your pump?
Yeah, I did check the location of the fuel line running forward to make sure it was clear of any exhaust pipes. I just ordered a aluminum radiator with electric fan and relay. I'm going to try and get rid of some of the heat under the hood first and see that helps. It has never cut out it when it's under 75 degrees outside. Right now the car has a 4 core with a flex fan. Not great setup for a 300 hp 5.0. on hot days. It popped the cap into the overflow when it hit 80+ degrees out Saturday. So I took out the fog lights and brackets to give more air flow through the grill area and now ride around with the heater fan going. Wife complains its hot on her side, I said don't worry I going to get it fixed! But at 80 degrees out it did not stall or cut out. So I think I'm on to something.
If you're having an issue with just a 5 degree variance (75-80 degrees), sounds like you really have a cooling issue. I have a 4 row and a flex fan and run a maximum of 190 degrees in 100 plus degree weather in my warmed over 302.