Maybe
this book ?
A couple of small mentions on the Allpar engine pages:
"What made the flathead so versatile was its dependability and torque. The largest flathead six Chrysler used in its automobiles was 265.5 cubic inches that produced 218 ft/lbs of torque at 1600 RPM. So, at just off idle, this engine produced maximum torque, making it ideal for the applications above.
In comparison, the last flathead 8 was used in 1950, with 323.5 cid and 270ft/lbs @ 1600 rpm. Although the 8 was more powerful, most people found the smooth power produced by the six was sufficient, and so a vast majority of older Chryslers found today are equipped with sixes. These figures are at the rated compression of between 7 and 7.5 to 1.
Webmaster's note: the flathead eight-cylinder engine was used in a large variety of vehicles, and was a straight-eight (not a V8) design. It was used in the revolutionary Airflow models - they had to be lengthened to accommodate it."