Muffler hook/body repair basic questions


#1

I need to know if some of these ideas I have below are stupid or not.

by accident, I drilled out a captive bolt (1.25 pitch, approximately 5/16-inch) that held the muffler hook. That is, I thought it was a plain bolt, but it in fact was sealed into the body. Since the damage was done, I did the same thing to the other of the pair. so now there are two holes instead of two bolts. this is a 1987 Porsche 944 NA, manual transmission.

even though that was stupid, I have some other ideas below that I can check the stupidity of, and will help me learn some basics as well. my latest plan is to put a carriage bolt in the hole - because the top of the captive bolt was quite flat - then the hook, put a washer on the hook side, and tighten to some good torque value (that I must search for) a lock nut.

however, I am wondering about the vibration and heat there. hence, some other ideas I had that might apply in part or combination:

high-T epoxy paste (“ThermoSteel”) to seal the bolt to the body hole
high-T Loctite on the threads (perhaps red color?)
PLAIN epoxy to glue bolt in hole
anti-seize on the threads (probably not though, if never planning to remove the hooks after refurb).
additional nut and washer on the body side for additional stability - maybe needs a plain threaded rod instead of bolt
some type of lock washer (too weak?)
nylon lock nut will melt, so use a different one like distorted thread?

… perhaps more thoughts occur to me, but I’ll stop while I am ahead.

BTW this is related to this thread:

http://community.cartalk.com/discussion/comment/3032751#Comment_3032751

I changed a few things since nobody replied, indicative of poor formulation of the question.