The head bolt next to the header pipe WILL get loose over time.
The reason it gets loose is that the head gets so hot in that area that the aluminum will actually get soft and compress.
The reason for the heat disperser under that head bolt is to HELP prevent that from happening. It does really help!
If you mark that head bolt on a new engine and check it mid way through the season (depends on how many races) you will find that it hasn't moved at all. It hasn't actually turned or loosened.
Hear's what i'd recommend. Mark the head bolt and a corresponding spot on the head with a sharpie. Use a rachet or breaker bar and loosen the head bolt 1/2 turn and then use a good inch pound torque wrench and re-torque it to 210" pounds. Next check to see if the marks you made with the sharpie line up again. Most of the time they won't line up because things have compressed a little bit.
Before Briggs installed the heat disperser we would see the flange on the head bolt distort and the aluminum under the head bolt get distorted / dished.
My suggestion for those that have the proper tools and ambition is to remove the header pipe, mark the bolt and head with a sharpie, then loosen the head bolt 1/2 turn and re-torque that head bolt 1/2 way through the season. While your at it put a new header gasket on also.
If for any reason you have to remove the header pipe i's suggest checking the head bolt also.
Good luck
Jim