Some photos of experimental paint scheme named Dazzle Camo:

http://aviacaoemfloripa.blogspot.com.br/2011/01/p-51-mustang-em-camuflagem-exotica.html

The dazzle was applied to a an Alison engined P51 not a P51B/Mk III.

Looks like it made it much easier to spot in the sky from the ground. Not to mention it's one Ugly camo pattern.
Joel

Squadron / Signal published a nice set of bottom and side profiles for the scheme in Allison Engined Mustangs Walk Around. It was supposed to confuse enemy gunners trying to line up their shots. I don't know how effective it was at that but it makes for a model that catches the eye.

Paul, I'm assuming that since the camo scheme was never adopted, it fell short of it's intended goals.

Joel

More to the point it was too finicky, manpower intensive and expensive to apply for the results it got them. The standard USAAF Neutral Grey was almost as effective and far cheaper.

a bit on Dazzle camo.

In 1917, the British Royal Navy pioneered the “Dazzle” camouflage paint scheme which often consisted of bold stripes and bright colors. The patterns were not intended to hide the ship, but rather to disrupt the outline so that size, range, speed and heading would be difficult to determine – preventing the enemy from accurately targeting the vessel. The United States was one of several nations to adopt the practice and experiment with different patterns through the end of World War II. “Dazzle” schemes largely faded from use because there was no clear evidence of their effectiveness, especially against technological advances in radar and rangefinders. “Dazzle” was however credited with boosting morale of crews who took pride in the unique and intimidating appearance of their ship.