Type 60 106mm Tank Destroyer

In the mid-1950s the Japan Ground Self-Defense Force contracted for one prototype from Komatsu (SS1) and Mitsubishi Heavy Industries (SS2) powered by a 110 hp six-cylinder diesel engine and fitted with two 105-millimeter (4.1 in) recoilless rifles. They were delivered in 1956. A second series of prototypes was built with 4 recoilless rifles, but adoption of the American M40 forced the reversion to two weapons. A third series of three prototypes was built by Komatsu as the SS4 that were heavier with a more powerful engine, a new transmission and clutch and a two-speed auxiliary transmission. They were accepted into service in September 1960.
Starting in 1974 a 150 hp Komatsu SA4D105 air-cooled, 4-cylinder diesel engine was fitted.
http://en.wikipedia.org/wiki/Type_60_Self-propelled_106_mm_Recoilless_Gun
http://www.militaryfactory.com/armor/detail.asp?armor_id=322