72 Dart Struggles and Dies today, Why?

I was going to take my 1972 Dodge Dart (318 engine) to a car show this morning. I set the choke and started it. It wasn't a cold morning, 55 degrees outside and the car is parked in the garage all the time. Kicked it off of fast idle and struggled to run, then died. I got restarted but as soon as I take my foot off of the accelerator it struggles to run and dies. It was running good 2 weeks ago when I drove it last, I did not get to drive it last weekend because it was raining all day Saturday and Sunday. Went to O"Reilly Automotive and got some Heet, but tried it again after about 8 hours and no change. Any suggestions?

Thanks for your responses in advance.