I've had this same problem for the 5 or 6 years. It runs just long enough to get out of the driveway, then I usually have to tow it home. I've had the carb apart several times. A couple of weeks ago it was flooding and blowing gas out the top of the back barrels. The rear floats had a little gas sloshing in them so I replaced them. All the lines and filters are new. I've tried to stay away from the timing even though I know most problems that are blamed on the carb are usually electrical. I don't see how the time could have got off. The distributer hasn't been out to get off a tooth. I'll take the governor line off and try advancing it and see if it makes a difference. I can't get it to run long enough to use a timing light. I decided I wanted to show it at our show in town next month and I want it to make there and back under its own power.

'65 C-10, 65 L-60, 65 C-80, 72 C-60 & and a bunch of old Chevy cars.
Never time to do it right, always time to do it over.