1964 Dart Owner - In Over My Head

if you got anything left of that stud once you remove the manifold pack, heat it from the top and touch a candle to it on the bottom. The heat will draw the wax into the threads and may provide enough 'lube' to get it free with a set of good vice-grips. if not, center punch it (important) and drill out (try a left handed drill bit first as it may turn right out without any more tension on it). I have had little luck with EZ outs, More luck with a straight drill in progressively larger sizes until I can pick out the thin shell with a punch and hammer. Brass nuts help with not seizing on the studs once they are replaced. And the special washers are important to provide the proper torque to the manifolds so they can slide on the gasket as designed. If you dont use them, you can crack your exhaust.