347 stroker missing under acceleration?

i have a 1978 mustang with a 347 stroker, it has a holley 600 cfm intake a cam and a weiand intake. i have put new plugs wires and cap on the car but it still seems to miss under acceleration. it has a new ICM. all it may need is a good tune but i have tried that and i cant gat anywhere, can anyone help me??