Specification of Kawasaki Ki-61-I-KAIc Army Type 3 Fighter Model 1c:
One Army Type 2 twelve-cylinder liquid cooled engine (Kawasaki Ha-40) rated at 1180 hp for takeoff and 1100 hp at 11,480 feet. Performance: Maximum speed 366 mph at 13,980 feet. An altitude of 16,400 feet could be reached in 7 minutes. Service ceiling 32,810 feet. Maximum range 1120 miles.
Dimensions: Wingspan 39 feet 4 7/16 inches, length 29 feet 4 inches, height 12 feet 1 11/16 inches, wing area 215.3 square feet. Weights: 5798 pounds empty, 7650 pounds loaded.
Armament: Two fuselage-mounted 20 mm Ho-5 cannon and two wing-mounted 12.7 mm Type 1 (Ho-103) machine guns.
Another source, #s are close. 366 mph quoted here. I have a feeling the Ki-44 is within 10mph of the Ki-61 for most versions. I still maintain it was not a superior fighter overall. I would have to see a breakdown of the Ki-44 versions speed #s and corresponding armament, and compare it to the Ki-61 versions.