Ford 351M or 400M, what does the 'M' stand for?

[demarpaint]

Fast forward to 2015, the M could easily stand for Mexico.

 

[Norm Olt]

The "M" stood for MILQUETOAST, as in "Casper..."!

 

[TiredTrucker]

Yep, Modified Cleveland. I owned a couple of 351M motors and loved them.

 

[SatinSilver]

The Cleveland engine plant in Brook Park,OH was recently shut down:

http://www.cleveland.com/business/index.ssf/2012/05/ford_to_close_cleveland_engine.html

I live about 15-20 mins away from it.

 

[TFB1]

Originally Posted By: 2015_PSD
Originally Posted By: bdcardinal
Modified.
+1 - I have also heard "Michigan".

Something no doubt started by those who didn't/don't have a clue... When introduced in '75, Ford stated M was MODIFIED(check the shop manual for '75)...

Basically it's a 351 Cleveland built in the taller 400 block that uses the big block transmission pattern, nothing more, nothing less... Lessened amount of castings necessary, no need for two separate blocks...