Milled out the breather opening

I didn't change the "timing" of the opening (when the breather gear's window enters and exits the window in the case), as it isn't needed for this build, but down the line, if I bump it to 93", I'll need to widen it to match the new stroke.

You can see in my previous postings what the opening looked like. With a Dremel tool and wand attachment, with a cutter attached, I ground down the rough spots and squared up the opening a bit. I also "flattened" the leading and trailing edges of the window.

I also cleaned up other areas of rough casting marks in the cam cavity.