Ivy: New Rear Brake Doesn't Fit!

Thought I got a good deal when I picked up this new rear brake for just $25.  But not much of a steal if it doesn't fit.

It actually appeared to fit just fine but then I couldn't get the spacer in place trying to remount the wheel.  I thought I just had everything out of alignment like I did before but this time I didn't try to pound it in with a hammer.

Instead I set a level across the hub and then dropped a ruler to the ground to measure the distance.  In the end, I found that with the old brake the total width from side to side was about 135 mm.  With the new hub, that was pushed out to 140, and clearly too wide to fit.

The two brakes did have a slight difference - different versions?  I haven't bothered to check the parts guide.  Either way, one works and one doesn't.  Maybe I'll compare it to Red's brake and see if it's really the odd man out.  Or maybe Red's brake will work for Ivy and the new brake will work for Red...?

Also continued working on the engine support stool.  Just got it to barely fit underneath now.  I'll have to try dropping the wheel to make the final adjustments.