Has anyone ever removed this bolt before?

It's in there really tight. I've soaked in CRC, I've tried with a power-bar, with a power-bar + extension, with a rattle-gun and heated it with a little butane torch. But can't get it out.

Clymers does seem to say it's 100ftlbs of torque which is a lot.

Anyone ever removed it? What is that bolt even for and why is it in there so tight?

I can't imagine anything working better than an impact wrench...
It sounds like you've tried it,... but, I'd give give that another repeated try, with 10 or 20 repeated 5 second bursts...
Any more lever torque will likely twist, or strip, the head off...

Beyond that,.. it may require a trip to a machine shop...
...those guys seem to know metal voodoo... ...

Then again,.. that bolt may be doomed to snapping off... ...

If it is too tight for a good  impact on a compressor thats UP,  & done the way Rowboat said then youre gonna hafta go at it with serious stuff to keep from twisting it off. More Torque isnt the answer. Thats an invitation for a costly trip to a machine shop. If you dont have a torch,maybe you can rent one. You need a brazing tip. You need to put enough heat on it fast enough to be able to heat that neck the bolt is in & not allow the mass of metal to draw it out as fast as its being applied. So, a gas powered soldering tool wont cut it. A propane torch for soldering plumbing
isnt focused enough, a brazing tip is. A damp rag draped around the background stuff & held back outta the way, A bowl  of ice cubes at the ready. Heat a line from bolt shoulder down the neck. Put an ice cube on the head of the bolt then hit it with the impact. Do that till you win. YOu may have to widen that line, you may have to add more heat, start with the least amount of heat you think willo give you the edge you need.
Time spent here beats time spent hauling the motor to a shop.
Its been noted that there is some thread lock involved,,just a good warming up all the way around mite just soften it enough, on second thot, Id start with that. Dont hafta go to a color change, just hot enough that if you grabbed it, youd howl like a gut shot panther,
Dont let Big heat get deep in there,, theres stuff back in there that wont appreciate it,
I have been known to use a blow gun to drop my compressor down enough to make it kick in, so my impact would be getting max pressure when I need it.
Ive seen portable torch kits for rent at the rental place I use,
BUT., If youve ever wished for a torch, now is when you could sell the idea.
I pretty much HAD to buy my  Oxygen tank ( Dont buy acetylene, get a small propane tank,much cheaper & works close enough to the same. I watched a guy cut the bearings out of an A.C. clutch In the vehicle & didnt hurt the clutch or the compressor with propane, so, its good enough) because a friend sold me ( virtually Gave me) a Smith torch & every brazing tip they made for it,, I hadda buy the rosebud,,when I smashed the rim up on my backhoe getting away from a fire,,Took 4 days & 2 bottles of O2 to pund it back into shape.
If you do get a torch, buy the tank. REntal will eat you up.

Go slow, walk away if it gets frustrating, winning is all that matters. Winning quickly is nice, but losing quickly sux,, losing at all sux, but if you hurry & screw up, youll kick yourself, If you go slow & THINK your way thru, you will either win ( which I believe you will) or lose. If you lose after being careful you wont feel near as bad,,

Is there anyone reading this who doesnt fully understand HOW I know all that?

WD, as much as I enjoy your insightful & informative posts, on this thing, Im leaning toward a more subtle approach, since the consequences for a headless bolt buried in a hole with thread lock would be severe. Im all over the Bigger Hammer approach with my oilfield time teaching me how to get meaner when things dont wanna play. This just doesnt look like a great place for that,.

IDK what kind of pressure this can handle from the end. IDK if smackin the head of the bolt with a hammer would harm a seal or whatever, but
I have seen stubborn bolts get easier with a real solid blow to the head.
Seems to work on people, too..

While I was in town I was thinking about this,,smacking a bolt thats got locktite on it wont help.,.

When I took mine off a while back, I used a breaker bar with a 4' pipe over it.  Still had to pull extremely hard to get it to move.  Once it turned about half a round, it wasn't too bad anymore.  It did have thread lock over about half the length of the threads.

+1 for JoG's suggestion. Big heat will make the threadlock let go. I'd be using a single hex impact socket, too. If you could make up a steel or aluminium plate with a hole in the centre for the bolt to poke through, you might save some other parts from stray flameage.

Heat and impact, you'll be happy and drinking a beer in no time  

I've tried heat and impact..

I'll try more heat

.. and more impact