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The Franklin O-400 (company designation 8AC) was an American air-cooled aircraft engine of the 1940s. The engine was of eight-cylinder, horizontally-opposed layout and displaced 397 cu in (6.5 L). The power output was 235 hp (175 kW).
Variants
8AC-398
200 hp (149 kW) at 2,600 rpm.
8ACG-398
235 hp (175 kW) at 3,500 rpm. The 8ACG-398 was unusual in using a reduction gearing for take-off and direct drive for cruising.