I’ve noticed that a lot of online sites state that the T14 uses an engine called the Ford GAZ V-8. This engine is part of the Ford GAA family, but according to everything I’ve found, it is slightly more powerful at 520 horsepower. This includes a video made by the Tank Museum in which they discuss the T14 and A33 Excelsior tanks. However I haven’t found any primary source that explicitly states this horsepower value on the T14.
I have, however, found one source that could explain this extra horsepower, that being AD-B965 290 “FIRST REPORT ON ASSAULT TANK T14 AND FIRST REPORT ON ORDNANCE PROGRAM NO. 5621” (found here as an online PDF).
This source states that the T14 uses the GAZ engine which is rated at 500 horsepower at 2600 RPM and is similar to the normal GAA except with some differences to the carburetor and magnetos.
Page 25 of PDF.
Page 176 and 177 of PDF.
Seemingly this contradicts all other information about the GAZ being more powerful. However, one other thing that this source states is that the GAZ engines used in the T14s that were tested had been governed to 2900 maximum RPM.
Page 72 of PDF.
Page 175 of PDF.
So as far as I can gather, while the engine itself wasn’t explicitly more powerful, it was capable of going upwards of 2900 RPM. One of the pages explicitly states that the T14 was tested in 2nd gear using multiple engine RPMs, including 2700.
Page 179 of PDF.
In fact, in the very same page is included a table that has calculated top speeds for each gear of the T14 at 2900 RPM.
A couple of things can be derived from this table, including the engine RPM that is necessary for the 24 MPH top speed of the T14. By doing simple maths we can conclude that the engine would need to be running at at least approximately 2700 RPM if we disregard any and all track slippage.
TM 9-1731B provides a power and torque curve for the Ford GAA V-8 engine, and at 2700 RPM it seems the engine reaches roughly 520 horsepower. However even at 2800 RPM the engine power is still climbing, achieving 525 horsepower.
I’d really love to get as much information on this as possible. Potentially it could even lead to a buff on the T14.