Ford GAA engine

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Immediately proceeding World War II, Ford developed an aircraft engine similar to that of the Rolls Royce/Merlin and Allison engines of that era. It was a 60 degree V-12, all aluminum (block & heads), dual over cam, 4 valve engine. The intention of this design was to help Ford break into the anticipated large market for fighter engines. This engine was built to typical aircraft standards: It was a light, high performance and highly reliable engine. Everything was safety wired or staked with close attention to detail on every part. Available information suggests that this design performed well.

However, this engine never went into production as an aircraft engine due to the US Navy's decision to only use radial engines for its aircraft, and the Army's contractual commitments to existing engine manufacturers.

With the approach of war, increasing orders for the Sherman tanks were causing supply issues with the existing engine. The US Army decided they needed to source an engine supplier. So Ford removed 4 cylinders from the design and it went into production as a V-8.

Ford GAA
Ford GAA engine
ManufacturerFord Motor Company
Production1940 - 1950
Fuel systemNormally aspirated
Fuel typePetrol
Power output450 hp (336 kW) @ 2600 RPM
Compression ratio7.5


The Ford GAA engine is an all aluminum, 32 valve, DOHC, 60 degree V8 engine produced by the Ford Motor Company during World War II. The engine was used to power several models and derivatives of the M4A3 Sherman tank. The engine displaces 1100 cubic inches, and puts out over 1000 ft lbs of torque from idle to 2600 rpm. Maximum rated horsepower was 525@2800 rpm though most models were rated at 450HP.


  • The Ford GAA was used in the M4A3 (1,690), M4A3(75)W (3,071), M4A3(76)W (1,400), M4A3 (105) (500), M4A3E2 (254), M4A3(76)W HVSS (3,142), M4A3(105) HVSS (2,539), M10A1 (1,413), and M7B1 (826).
  • The Ford GAF powered the M26 (2,222), M26A1, and M45 (185).
  • The Ford GAN, powered the T23 (248) and M4A3E2 (254).
  • In order to meet the need for a larger engine, Ford resurrected the V-12 as the GAC, which produced 770 hp and powered the T29 (6).