1979 242 Taking the car for inspection so I could put it up for sale (running good). Pulled up to a stop, and the car died. Won't start. Looked in the oil filler cap, things are moving while cranking. Got spark on the number 1 plug. After sitting about 4 hours, the car will fire on the first crank, and then fail to start. I'm seeing a puff of white smoke out the exhaust. No water in the oil, or oil in the water. Changed out the fuel pump fuses. Swapped the fuel pump relay with a known good one. Less than 5k on both fuel pumps. Originally was somewhat low on gas, but have since added five gallons to no avail. Any troubleshooting ideas? Thanks in advance.