A stock 250 should be a press in stud,slip a short length of small pipe, socket, or something similar over the stud leaving some threads exposed, Then using the rocker nut , tighten the nut and the stud will draw out. You may have to use washers as shims to prevent the nut from bottoming out as the stud draws out.If the stud is bent severely,you may want to heat the stud red hot and gently bend it straight.Bent studs may crack the cast iron boss it's pressed into, check closely before pulling the stud.I have in my "farmer" days brazed up cracked stud bosses on small block V-8's with the head in place with succes on non hi performance engines.To reinstall the new stud,clean the hole with brake cleaner, apply Loctite to the stud, screw on the nut, then cover it with a socket, use a heavy hammer to drive it home.There is a tool made for this, but this method has worked out fine for me many times.
