From the above link
"What did come from testing the aircraft engine was just another Chrysler accomplishment that went by unheralded but was nevertheless noted later. This was an overhead cam V-16 engine dubbed the XIV 2220; the 2220 represented the displacement of the cylinders, in cubic inches. That equals over 36 liters.
For testing, a P-47 Thunderbolt, the largest and heaviest single-seater in the Air Force at the time, was selected. Some modifications were made to accommodate the XIV 2220; when done, the slimmed down nose helped reduce the drag produced by the big round radial engine.
Preliminary testing showed promise. The big fighter was coaxed slowly into higher altitudes and higher speeds. Finally the go ahead was given for an all out test. At 15,000 feet, the huge plane, under the Chrysler V-16's power, broke the 500 mile an hour barrier, around 70 mph faster than the original engine. No one thought it was possible for a piston engine to achieve that speed in level flight.
Thanks to accurate radar timing, it is beyond doubt how powerful that engine truly was. Flat out, it pulled the huge P-47 along at 504 miles an hour.
Just to be sure, the test P-47 went out the next day with a different test pilot and again level at 15,000 feet, went through the 500 mile an hour mark. Hand shakes and elation went all around. However, the engine never went into production. The important thing to keep in mind about this engine is that it was a Hemi headed, push rod valve activated type. It survived the war, and now is on display at the Walter P. Chrysler Museum in Auburn Hills, Michigan. [According to Bob Nist, a Chrysler ad in Space Smithsonian mentioned three of these engines made; one is at the Smithsonian, and the third, according to Don Wagner, is in the New England Air Museum in Connecticut. A Chrysler Museum display says that five were made."