I've seen several engines with the induction port ball milled (I think that's the way they do it?)
The Magnum .52 I have, and the 2 Evo's, and the as mentioned AX...
Several of my r/c car engines have it too...

I did a K&B 40 and .61 years ago with JB weld and it hasn't broken loose (yet anyway) maybe because of careful prep.
I roughened the area w/ a Dremel grindstone, after a thorough cleaning w/ acetone. I put the JB weld in and set the crank at an angle to cure. Then I baked it in a toaster oven at about 200* for awhile, then after it cooled, I went in w/ the trusty Dremel and put the radius in there...