That’s right, the biggest and baddest ass production Ford built V8 in the company’s long history was an 1100ci, all alumimum, dual overhead cam, 32-valve piece that made over 1,000 lb/ft of torque just off idle and more than 520hp when run at its happiest RPM. What car was this thing in? It wasn’t. The engines were built and installed into Sherman tanks for WWII. Originally the mill was designed as a 12-cylinder for powering airplanes but the Army Air Force decided that they wanted to use radial engines in all of their war birds. Ford shelved the design until the government came looking for something to power the Shermans with and they lopped four cylinders off the end and voila! A V8 for the ages was born.
Using all of the modern tech we mentioned above along with pent roof style combustion chambers in the heads, a 60-degree cylinder bank angle (to fit in the originally planned airplanes), and a host of other forward thinking technology these engines were well suited for battle. They were supposed to be run at 2500 RPM and governed there, but WWII tank crews would circumvent the governors and run them up to about four grand where the valves would float. Panzer tanks were faster and the Sherman crews wanted the extra revs to chase ’em or haul ass away from them!
With only 7.5:1 compression these engines are well suited to being turbocharged and a few tractor puller types have done it and made somewhere in the neighborhood of 2,000hp with a pair of large by huge twins feeding the engine. Revs were and never will be a strong point in this engine. The bore is 5.402 inches and the stroke is an astonishing 6″! The four valve heads use a pair of 2.12″ intakes and 1.90″exhausts. Being aluminum, the engines can be set up with modern stuff and come in less at than 1,000lbs of total weight. Dressed in WWII combat trim, this aluminum engine still weighs 1,440lbs! As we said earlier, the engine was rated at 1,000 lb/ft of torque from 1,000 RPM all the way through the advised RPM limit of 2500 RPM. That’s bad ass stump pulling power!
The Allisons and Merlins get all the love, but the Ford GAA was one bad romper stomper in its own way. We’ve seen a couple builds with people using these engines in pulling tractors and at lead one guy is ‘horning a GAA into a Mustang. Gnarly!
PRESS PLAY BELOW TO SEE A MIGHTY FORD GAA SHERMAN TANK ENGINE FIRE UP AND LITERALLY MAKE FIRE OUT OF THE PORTS! 1100CI OF FREEDOM!
Turn your volume way down because the audio from a cell phone sucks !
We finished putting a new GAA into our Sherman tank last summer. Was a hell of a feeling when we fired it up for the first time, you can feel the thing hit in your chest when its running. I had to call my doctor, the erection lasted for more than 4 hours haha