Motor dies after startup.

Did an oil change, with a new oil filter.

Changed out coolant.

(Wasn't sure if these were related, but they needed to be done, so I did it anyway.)

Also found out that the thermostat was missing. Like, no one ever installed one. So I put one in.

(I forgot to mention that this is not the original motor, but it was one that my friend drove around in for some time. He pulled it to put a 360 in his Dart. I would assume he never had a problem driving it with no thermostat.)

Checked connections from the coil to the distributor to the spark plugs. Checked each spark plug (they looked ok, slight browning at the tip). Put them back in at 30 ft/lb as prescribed by the manual. Checked spark plug connections to the distributor.

Next I checked for vacuum leaks. I replaced old rubber caps that were cracking. I tried to seal up anything that didn't go out to something on the carb. And while the motor was idling I sprayed some carb cleaner around the seams of the carb, where the carb meets the intake, and where the intake meets the motor, to see if there would be a change in rpm. Nothing.

Except, the motor shakes. A lot. And there's the smell of oil, I'm not sure if it's burning oil.

After all that I tried fidgeting with the carb settings to see if I could smooth out the idle in park. I managed to, at one point, but the motor shakes pretty hard when I go into reverse or drive.