Before you go throwing money away on new parts that won't last like the old ones, and possibly replace perfectly good parts, test test test.
Start with the Coolant Temp Sensor. It's in the intake manifold. Testing instructions are here:
http://67-72chevytrucks.com/vboard/s...d.php?t=425788
If that's good, check for fuel and spark when it dies. Fuel pumps die slowly or intermittently, but rarely when the engine is hot. The pump is in the tank 15 feet away. Engine heat has nothing to do with the fuel pump dying. Pressure test would be correct if it sputtered or had no power.
In closed loop, the ECM is relying on all the sensor data, so it's likely a sensor or electronic piece that's failing. All are easy to test or see data with a scan tool. MAP, TPS, O2, etc.
The ICM under the distributor is well known for dying in the heat especially if heat sink compound wasn't used or not adequately. Just because you replaced a part doesn't mean the new part isn't DOA. Many new parts are junk, especially the cheap ones. Stick with Delco or Standard if you can.
EGR may be to blame as well, but you can test it before throwing money away at it. You also need to get the correct one. Info here:
http://67-72chevytrucks.com/vboard/s...d.php?t=549711
You can test the EGR with a vacuum pump.