Debugging a hot stall in my '67 Spider

[DinoinATL]

Let me provide the background conditions and maybe someone with more knowledge than I can help me debug this.

This week i took the Dino for a long highway drive, my speed was a continuous 70mph for 2 hours and the air temp outside was about 80 degrees - warm day. The car ran great. The water and oil temp guages were normal the whole time - needle was right in the middle of the guages. The gas guage was about 1/4 fill. At about the 2 hour mark and while I was traveling at 70mph, the engine shuts off with no warning. I lost speed until the car coasted to a stop on the roadside. There was no warning that the car was having any problems. I tried to restart the car immediately and it wouldn't start - it tried to crank but wouldn't fire. I tried several times to start the car without success. I then waited about 30 minutes (i was on the phone trying to find a tow), decided to turn the key one more time and it starts up. Fortunately, I only had about 10 miles to my house and so i drove it at the slowest speed I could get away with. The car was very clunky from that point onwards, bucked a few times as I pressed the gas, stalled again at a light (started up immediately), but I did make it to my driveway where it has been parked for the last few days. The car will start but I haven't had the time or courage to take it back out for another drive.

Any idea what caused this? My first inclination was that perhaps the engine overheated (despite the guages suggesting otherwise) and a kill swtich turned off the engine. There were zero signs of the engine having any challenges before it stalled so I don't think that was the problem. Or perhaps the kill switch erroronously activated? Is there a kill switch on a '67?

The car also has a MSD ignition box - could that have failed or overheated, causing the engine to turn off?

Any help would be appreciated.
-Dennis

[agnatus]

There could be many reasons for this.
I would suggest checking the fuel supply system. Perhaps there is some contamination in the fuel line causing the fuel pressure to be too low—this could originate in the tank, where debris might be blocking the line leading to the fuel pump. It’s also possible that the fuel pump itself is no longer functioning correctly, or that the fuel filter is clogged; the issue could be anywhere along the line, right up to the carburetor.
You might want to try connecting a pressure gauge between the fuel filter and the carburetor to test the fuel pressure.

If the fuel system isn't the cause, the next step would be to check the ignition.

[Tobi]

Checking the fuel system is a good idea. I once had a problem with the fuel pump under heat conditions. It turned out that the ground connection of the fuel pump was corroded.