It could be Oz conditions Beans, or perhaps I have just been lucky, but there was no corrosion in the couple I have done. In fact one still had oil on the studs & one grease. Neither had run in some time, so it was not fresh oil or grease.
In both instances, once cracked, they screwed out by fingers. I was surprised at this, as all the posts about head removal had reported considerable corrosion.
You should be able to order high tensile allthread rod from an industrial fastener supplier that caters to the engineering industries. It's where I get all my fastening hardware from.
"Keep calm, relax, take a deep breath, focus on the problem & PULL THE BLOODY TRIGGER"
'80 Triumph TR7. '97 Ford Falcon Longreach 'S' ute, '98 MG-F. '83 Jaguar XJ6 Sovereign S3.