1966 chevy truck help.

[joe1966]

I have a 66 chevy c10 2wd 4 speed. with 350 small block with hei disrib and AC delco plugs and streetfire or msd wires pretty much. When i go to start it up sometimes it will run bad like kinna really choppy sounding like the plugs are dirty, i will kill it then go under the hood and take off each plug wire one by one then go and try it again and it will run really smooth, what is wrong! its doing it more and more each day. the plugs are probably a week old and the wires are probably a month old or less. thanks! joe