340 Starting issue

When in got my current Duster, we couldn't get the 318 to run, so pulled my 340, 727, and 4:10 set outta the Sat. Car would idle in the driveway for 20-30 minutes. Drive it? It would shut down after a mile or so. Got her home, and pulled Sender.. looked like the inside of a volcano or something in there...... that was the problem