I tackled these this weekend and had an issue like some with the header studs stripping out. Luckily i was able to chase the threads with a tap and die set however it was nearly a bust. I found that my secret weapon here was my other half who is a mechanic as well. Her arms can get down behind the headers and she did a lot of the confined space work.
Here you can see the thread tool as i chase the threads on the block.
...and here you can see the smoke rising from the headers thanks to the DEI wrap. I actually had people trying to get me out of the car at a stop light on the way home because they thought the engine was on fire.
Sorry for the pics being sideways....im too lazy to go back and rotate them then re-upload.