84 Ford Van E 150 Cranking with key off at times

At times my old ford van when turning the key to start it if it won't start I normally will stop turning it to start position and pump the gas and try again at times with the key off it will still make like it is cranking, once it was running and sounded like it was cranking at the same time I turned it to start and the cranking stopped and it then was like normal again. Tonight I started it and it was ok normal but this happened about 3 times now. I had the starter checked they said it was ok, I put a selinode on the fire wall it had the 2 prongs on it my old one had one but the counter man said that is ok just use one I done this a while back when I put the new battery in before this problem happened. I was told maybe it is the ignition switch I do not know the first thing about changing that. It is a 84 Ford E 150 Van 302 cu in. Thank You, Buddy R. Takasch