Rodney, if the plugs are black and dry (sooty) it's probably either got a weak spark or it's running too rich. Also, a lot of short trip driving or driving with the choke pulled out will do this. I think you are running AutoLite 306 plugs. Try a plug gap of .028. Some books say .035 but that is only for resistor plugs like the Champion R series. Points, .020 inch. Dwell is just another way to set points, using a meter to measure how many degrees of cam rotation the points stay or "dwell" in the closed position. A .020" feeler guage works fine though.
Another thing on weak spark, if you've changed coils, be sure the wire to the distributor is connected to the + terminal on the coil. If connected the other way it will run but the spark will be weaker.
I have a boat with a Chevy V6 motor and I only run it maybe once every 60-90 days. Unless I use a shot of starting fluid it's hard starting. Once it's been run, it fires up fine without any help.