312 motor.  Set the points to .015.  Car fires right up and idles.  Press on gas car dies. Checked points and the gap was now almost 1/8".  Readjusted and car fired right up.  Ran fine for a while, put into gear and died.  Checked points and found them to be completely closed.  Readjusted and started right up.  This time I was able to drive about 2 blocks and it died.  Looked at points and they were wide open.  Adjusted and started up and went home.

Checked each time to make sure the set screw was tight and it was.  Adjusted each time on the high point of each lobe.

Distributor is bolted down and does not move.

Little movement in the shaft but no more and expected.

Any ideas to what is causing this?

1957 Thunderbird

312