Nope, not big, small, nor mid-blocks. In the shop manuals and master parts catalog they refer to the engine by displacement, either in cubic inches or in liters. And only when they get to some point where there are multiples do they use a letter designation, such as 351W or 351M. But a 302 is just a 302, and a 400 is just a 400.

However, I don't recall them ever referring to the engine by series, meaning as the 335 Series for the 351C, 351M, & 400.

 

302 just a 302 ? You forget the Boss 302 and the Aussie 302C. Then the "351's" were actually 352 CID So there were actually 4 engines of the same displacement.

 

. All Chevy 396 motors were really 400ci. They just used the number 396 to be under 400 ci.

 

And no matter if its a small block, mid or big it always gets compared to a ford engine that has 60 more cubes. I like to think of it as a engine that makes small block hp with big block torque, but that's just me. Its a 400 ford, plain and simple.

 

If a 400 uses the same block as the 351M (not to be confused with the Cleveland) Modified,then how couldn't the 400 also be a "Modified"?
Wasn't the 351M a "Modified Cleveland" hence it's name "Modified" ?
I recall reading back along on it being the Cleveland base with updates.The Cleveland,that was......Modified.

Ford may have only listed in the M in the 351's name to separate it from it's Cleveland predecessor as well as to continue keeping it distinguished from the Windsor.Since there was no 400CI before it,they didn't bother to add the M designation.This IMO doesn't mean calling a 400 a "M" for Modified or even "MC" if you prefer for "Modified Cleveland" wrong.Even though ford never called them that (imho,just because they didn't have too),one can't argue that's not what they are..........or no? Just thoughts.

As for big or small block.They are a medium block.In between ford's 302/351w small block and 429/460 big blocks (There's more to it than this as already pointed out in this thread,but to keep it "Chevy comparison simple".)

So though perhaps never named such,they are 400 MCMB's - Modified Cleveland Medium Blocks.

Call them what you will,Iv always called them great engines.An overlooked great platform.A forgotten and lost gem.Hidden from view,from even the best of engine builders in their time.

 

The 351M came along 4 years or so after the 400 appeared, so a 400 wouldn't have been given the "M" designation. As it was, I clearly recall the 351M's appearance in the late 70's and it being referred to as a 351- Modified. Everyone had high hopes for it, myself included until it was driven. BIG disappointment, No power and horrible fuel mileage.

 

Ford never called it a Modified. We knew it as a Modified because it was a modified 400 - shorter stroke. Ford just called it a 351M. The only time Ford put an alpha suffix on an engine was when it had more than 1 of them. And, when they did that they used the first letter from the name of the foundry where most of those blocks were cast. So the 351 that was cast in Windsor was the 351W. The 351 that was cast in Cleveland was the 351C. And, most of the 400's baby brothers were cast in Michigan. So, speculation is that the M actually refers to Michigan - although Ford never used that term.

Anyway, in Ford's Master Parts Catalog they were the 351M and the 400. Never ever the 400M, 351 Modified, nor 351 Michigan. Here's a sample. And note that while there were both 351 M's and W's in use they used those terms, but as soon as the M was gone the 351 had no suffix.

 

sounds about right Gary.