A timing chain is easy to check as well, but I seriously doubt that is what is stalling the engine.
Pull the distributor cap and turn the engine just until the rotor starts turning.
Put a small mark where the timing pointer is on the balancer.
Turn the engine the other way just until the rotor starts to move again and mark the balancer there as well.
How much distance is there between the two marks?
Normal would be about 1/4 inch or so between the two marks.
The clues you gave point to a dirty idle circuit.
Try it, and I'll bet you are surprised.:D