Dump a little gas in to be sure the engine runs. If it does not, the nylon teeth on the camshaft sprocket may have stripped off so the camshaft is not turning. The camshaft drives the fuel pump but it also drives the distributor. If you also have no spark, that gear would be a good suspect. In case you DO have spark, when you test for it, stick a screwdriver in the end of a spark plug wire but be sure to hold it close to the engine so the spark can jump the gap. You have an HEI system with the really big distributor cap, and that spark IS going to go somewhere. If you hold the screwdriver too far away for the spark to jump, it will find another path to ground and that usually leads to more things to fix later.
If you have no spark either along with no fuel, remove the distributor cap and watch to see if the rotor turns while cranking the engine. If it doesn't, head for the timing chain.
With all that said, I suspect you simply have a fuel problem, and here's why. If anything would have happened to the timing chain or sprocket, the engine would have misfired, backfired, and died right away. Up to that point the fuel pump would have been working so the float bowl would have been full right when the engine died. You would still be getting nice streams of fuel when you worked the throttle by hand and watched in the carburetor. There's enough gas in the float bowl for the engine to idle for about two minutes or run on the highway for about half a mile.
The next thing is to check the gas supply system. Since you just bought gas, we know the tank isn't empty, but if it had just run out as you pulled into the station, there would be air in the steel line going to the fuel pump. Some pumps are not good at drawing a prime from the tank, but they work just fine when filled with liquid. I have one car that did that since it was new. I regularly ran it out on the highway, then dumped in a measured gallon from a can to see exactly what I was getting for mileage, but to get it to fire, I had to dump some down the carburetor. The higher speed of the running engine is what that pump needed to suck fuel from the tank. This is where you might want to dump some down your carburetor to verify everything else is working.
We can discuss further the next things to check, but most of the common stuff will not cause a sudden stalling as you described. The things I'm thinking of would have caused some other intermittent running problems before now.
Thursday, May 24th, 2012 AT 9:49 PM