I am sure this has come up on the forum before but I have looked through all the posts to no avail. One method I remember was the welding rod on an industrial welder was replaced by a 5/16” diameter rod,it was applied to each stud in turn which heated up and expanded thus cracking the corrosion. I remember Jim Best had to cut a head off once and had to make new brass water tubes. When he refitted the head he enlarged the stud holes to give more clearance. I once made some new head studs and had them parkerised and they never corroded a process they used on shafts to prevent fretting. Unfortunately the factory where I spent most of my working life and was able to do this is now a large housing estate. Best wishes Ted.
