- 97
- 9
SUre, it actually stands for nothing, ford used the "m" to identify them from clevelands. Most people before 74 who had 351m believed they were using clevelands till they were corrected. Anyways a 400 is a 400, no m should be attached, I think 351ms picked up the "m" due to the fact that most of them back in the early years were made in the michigan factry. Also 400 are high decked clevelands so 400 could be called a 400c...