I know I've seen it. Maybe it's with the article/discussion. Is your nose too long?
http://www.clstunt.com/noselong.htm

How about here http://stunthanger.com/smf/index.php?topic=15595.0

. . . your engine will ??. If your prop is too small, your engine will ??

Someone published a list like this on one of the forums a while back, which I can’t find.

For non-piped “modern” engines – say, LAs, FPs, and Brodaks – what are the tell-tale “signs” of over-propping and under-propping?

Underpropping - unable to get to top of circle
Overpropping - lose a lot of stunt contests but win the "static thrust bragging contest"

    THE single most important thing to know about prop selection on modern engines - *run the smallest prop that provides acceptable overhead/vertical performance*. The old conventional wisdom from 40 years ago about big props is just that - 40 years old. With current engines you can just let a smaller prop spin faster and get back the performance. Any bigger than the bare minimum creates a bunch of trim problems (and sorry, Leonard, running the CG back doesn't solve it).

     Brett

Underpropping - unable to get to top of circle
Overpropping - lose a lot of stunt contests but win the "static thrust bragging contest"

    THE single most important thing to know about prop selection on modern engines - *run the smallest prop that provides acceptable overhead/vertical performance*.  . . .
 . . .

I don't think there is any conflict -- unless I'm missing something -- between what Brett is saying vs what Randy said in his prop advice? I think Randy's advice is useful in applying Brett's advice.
 
". . .
 . . . 3. Correct Props: Props are also critical for achieving good engine runs; a prop needs to “load” the motor correctly without over or under loading the motor. It also needs to be the correct size and pitch to pull the airplane. This is an over simplication, but generally the diameter will be what you use to “load” the engine and the pitch will be what you pick to set the plane speed.
       Some of the things you will run into when over propping an engine are; hard to set the needle on the ground; the engine will unload a lot and go rich in the air; the engine will run hot, or not cycle very rapidly.
       When under propping generally you will notice the engine will also not cycle correctly. They at times will just 4 stroke thru everything, sometimes going into a 2 cycle at weird times.
       A properly loaded engine will use a prop that if running a 4-2 break, will come onto a 2 stroke a 10 O’clock and back to a 4 at 2 O’clock. There are variations on this; You can have a strong motor just beep 2 stroke at the tops of maneuvers, but you shouldn’t have one that 4 strokes uphill and switches to a 2 stroke on the downhill parts of maneuvers.  . . ."

     Larry Fulwider

I've had some recent experience with this.  I'd been trying to fly the Giles VI(65 in. 695 sq.in. 46 oz.) with an la 40, stock muffler.  I ended up with a 10/4 APC and 25% nitro.  Any less nitro and the motor would overheat and/or not produce enough power(very weather sensitive).  Any larger prop would cause the same problems with trying to figure it out compounded by the weather problems.

Found an LA 46 at the hobby shop and said why the heck not.  Bolted it in place, with the stock muffler, and the same prop, 10/11/11 fuel and it ran like a top.  11,200 rpm in a fast 4 cycle with very little effect from the weather.  Just tweaked the prop pitch a bit to slow it down to a 5.2 lap(62.5 ft lines).  I tried an 11/3 APC to slow it down, but it just overheated while flying the same speed.  So, get the right prop the motor will run happily.  Overprop and it will tend to overheat and be hard to set, as mentioned above.