You would find the design isnt that bad when you use the right tools. Ive probably pulled 1/2 dozen ford 6's heads off and never had a problem with the bolts and they are not that different to any other engine ive worked on either.

Use a good 14mm socket (i.e. impact socket, it is afterall a high torque bolt), crack eack in order before you undo them and you wont have any troubles.

some of mine were finger tight so i don't really know what it's like to have bolts that got stuck.
i'd be trying to weld a thick socket to it, get a breaker bar, and also around a metre or so of metal piping.
slide the metal piping over the breaker bar and turn.
hope that helps

Forget the welders and all the other stuff. Just get a centre punch and put a dimple in the middle of the bolt head. Next, grab a 3mm drill bit and drill down straight into the bolt about 14mm. Next, grab a 8mm drill bit and drill down again until you hit the bottom of the previous hole. Finally, grab a 13mm drill and do the same. The head of the bolt will fall off.

You should have just enough room to lift the head off the bolt. If it is one of the ones right at the back of the head you're in trouble. Would be easier to put a couple of bolts back in and pull the engine out. Then do as I described above. I've done this before and it works well. The head of the bolt will pop off and the bolt will then be loose. If you can drill it but can't lift the head off because of the firewall, just give the bolt a smack with a small cold chistle and unscrew it with a flatblade screw driver.

Hope that helps. Another trade secret lost.

Chris

as like everyone has said...

Use the inpact sockets
U can get a set of 9 from supercheap for 10$ and they actually last. As they also said loosen them off but dont take them out. The proper way to do it is work from outside inwards. That way it is easiest. I am so used to stripping heaps of holden adn ford 6 moters its not funny....