1967 Chevy Impala Car won't start.

I have a 1967 Impala. It will crank over but will not start. The Carb is getting fuel, from what I can see. I also can tell it is getting spark. What could be the problem? It has been sitting for 2 years. We drove it home 2 years ago and it was running okay, would cut out a few times and also was idling high. We started it recently and it started fine but still idle too high. We adjusted the moon shaped dial on left side of the carb and the idle went down and it kept running all night. Next day we start it again and it started, we pulled it out of the garage and it sputured and now it won't start. Any thoughts? Also it left black soot on the driveway while it was running.