Shouldn't be too big of job to have it welded up.  Just need to find a really
good weldor. (person, not machine.)  I'd be inclined to look into that before
I tried the adhesive route.  The problem with the glue/filler idea is the
thermal expansion of the block through a few heating and cooling cycles would
more than likely pop it right back off.

Of course, YMMV.

Jim