ok recently i put a 5.0 from a 95 gt and it had gt40 heads ported a big cam rollar rockers and a msd power coil and from some reason it wont stop spark knocking i guess that is what is doing no matter how mich i retard the timing or advance it and whenever i first start it up it idles good and as soon as i take off and stop a light or whatever it wont idle and dies and when i try to start it takes for ever or just wont start at all anyone know what to do?