I need some assistance with a serial number from a 1954 235 engine. I looked it up in the various old service manuals and Engine ID material that on the oldcarservice manual website and drawed a blank for the most part.

The serial number is as follows
052 I 707 F54M
I Think [ but not sure] the suffix F54 indicates 1954 made in Flint MI. I couldn't find anything on the type designation "M" that follows the F54 in the suffix. Is anyone familiar with this "M" type designation in the suffix?


Keith