RE: ESM P47 Build
I had a problem with muffler bolts coming loose on an MT57. Also the bolt heads were recessed into the muffler so not accessible.
What I did was to get longer bolts and loknut a couple of nuts to them so that when tightened the bolt heads stood clear. Then I drilled the two bolt heads and wired them together after tightening them up.
Seems to be working so far.
Terry