Death Touch,

Depending on how long the top bolts have been on will determine the scope of removal. Use a good 6 point box wrench and try to loosen the top bolts. If it breaks free with minimal effort work it back and forth, that along with the peneterating oil you use should do the trick, if the bolts don't break free right away with minimal effort DO NOT FORCE THEM...THEY WILL SNAP!!!!
If they don't break free use an acyetelene torch with a heating tip and heat up the ears on the head cherry red and work the bolt in and out slowly, you may have to reheat them a time or two but if you keep applying heat to them they won't snap. This advice was given to JC early on and he didn't have access to a torch in the begining and thus the "caper". The bottom ones can be accessed with a swivel 9/16" socket and a long extension. These will break loose and should come out with no problem. Reinstalling them is pretty straightforward, it would be a good idea to replace the old bolts with a new set of grade 8 bolts,get all the bolts caught and snug them up. then start from the center and work your way out tightening them down, get them as tight as you can using the box wrench and one hand. You can retighten them after the engine has warmed up.
As far as the starter removal goes I can't say how much interference you will have with the shorties however on the long ones the header has to be unbolted, the engine jacked up, the motor mount removed and the idler arm dropped. These starters were used in all the Y blocks and the FEs untill 1965. Hope this helps.

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Tony P.