The Kawasaki-built
P-2J (originally P2V-Kai, where "Kai" (改) means modification) was the last version of the Neptune to be produced. Work on the P-2J was begun in 1961. The first P-2J, converted from a P2V-7 (P-2H) performed its initial flight on 21 July 1966, and the last of a further 82 production P-2Js was delivered in March 1979. The Wright radial engines of the Lockheed P-2s were replaced with 2,125 kW (2,850 HP)
Ishikawajima-Harima T64-IHI-10 turboprop engines, using three-bladed propellers instead of the four-bladed units of late-model P-2s. The
Ishikawajima-Harima J3-IHI-7C booster turbojets, produced 13.7 kN (3,085 lbf) thrust, giving the P-2J a top speed of . The P-2J had accommodations for up to 12 crewmen. The forward fuselage was extended , with the tail surfaces being enlarged and their shape modified. AN/APS-80 search radar was fitted in a smaller radome. Updated avionics systems were installed, and these systems were much more compact than those used in other versions of the Neptune. The lighter avionics load permitted greater fuel capacity. The P-2J's main gear was fitted with two wheels each, rather than the one large wheel of the earlier models. ==Operational history==