"I am afraid you are wrong here. The American M1 6x4 armored car was built by James Cunningham, Son & Company in Rochester, NY."
Yes, I am wrong. I should have given due recognition to James Cunningham, Son & Company, the renowned coachbuilders from Rochester NY, who built the M1 armored car of which South Africa was to order another 22. But was it not built on a Ford truck chassis? The drive train probably wasn't Ford - at the time only Cunningham's own 479.4 cubic inch V8 gasoline engine could have produced the 131 horsepower as specified. Amazingly this small company also built their own transmissions but then again during their long history, James Cunningham, Son and Company made just about anything - from belt buckles to aircraft!
More pictures here:
Love those head lamps!