Clearance between tunnel and track

[Samebeef]

I want to start drilling in my tunnel. Goal is to install some Al square tubing to reinforce the tunnel to load it with backcountry gear + gas can as well as to support ski/snowboard racks.
I was checking for the clearance between the track and the tunnel and it is not much to say the least...
I don't know how much the whole suspension bend during riding and how close the track get to the tunnel.
Point is, is there enough space to accommodate the head of 1/4 inch bolt?
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[Coldfinger]

My 2010 M8 has very little clearance and track mis-alignment can reduce one side even more.

You can use large flat heat bolts. Some have allen socket.
You could grind down the bolt heads.
You could use carriage bolts and make the holes square with a file.
You could use steel rivets.

 

[IDspud]

Swather knife section bolts are 1/4” with serrations against a flat head that cut grooves into hole as they’re tightened that lock bolt with no need for a wrench, flush bolt head.

 

[MI1M600EFI]

?? You must be talking about side clearance... I put a 2.5" track on mine, and it doesn't rub, so there's at least 1/4" of extra clearance vertically... You could also try using "elevator bolts". They have a very large flat head, but most have a slight taper to them as well. Seems like a 1/4" bolt would be fine, but by the time you stack on a washer, it is getting a little taller. I bet it would still work. Even if it rubs a little occasionally, it shouldn't rub hard enough to matter. The track section inside the tunnel does not move with suspension movement, so aside from a little drift, the clearance you have is pretty much what you always have.