Modified Merlin engine for competition.

.
"Dwight-Thorn - Merlin"

-This job has been done by Dwight Thorn for his P-51, and he managed with both to reach 500 mph at the Reno races.

It turned out that with such a speed the engine burst, cracking the lower part of the airplane behind the propeller. 

-In the illustration it does not have the pressure carburetor at the rear bottom side, before entering the impressive superchargers.