I have a 78' Chevy step-side that originally had a 3 speed in it. I would like to put a 4 speed automatic in it, the 4l60e or whatever it is. I am pretty sure that those are electronic shift though. Is there anything special I have to do to put one in my truck or can I just bolt it up and go? Does it need any kind of ecm or anything? If so, can I get one just strictly for the transmission and where? Also, since it was a 3 speed on the column, does the linkage hook up and work still without having to do anything or does it need different linkage or what? All help and tips is appreciated.