How to tell the difference between a 351W,C,M

[MikeKC130J]

I am going to look at a 351W this weekend.
I don't want to get taken so how do I tell by looking at the motor if it is a 351W like he is claiming it to be? The motor is in a decrepit early 90's f150 u pull it type of deal.
Any help is appreciated.
Mike.

 

[Boss Hugg]

The front of a 351w (water pump and such) will look just like a 302. The upper radiator hose and thermostat housing will attach to the intake.

The 351c mad 351m will have the thermostat and upper radiator hose coming out of the top of the block. Also, this part of the block sticks out further than a Windsor because the timing chain has the block covering it. On a Windsor timing chain, there is usually an aluminum cover around it behind the water pump.

As far as the difference between a 351c and 351m... The m will definitely be wider than the c (because of the different deck heights), but I'm not sure how wide either one is. I'm thinking the m will have an m cast on the corner of the head.

Having said all this, I seriously doubt you see a c or m in a 90's truck...tho it COULD be done.


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[bronconut73]

Early 90's F-150 would not have a Cleveland or Modified. It would be a Windsor.

The Windsor will lookalmost exactly like a 302. It is slightly taller and wider but otherwise very, very similar.

The Cleveland and Modified are a completely different kettle of fish.

They are from a different engine family (385 series?)

One way to tell is the C&M were never fuel injected the Windsor was by '88.

 

[jckkys]

Just a couple of obvious things. The 351w valve covers are interchangeable with 289-302. 351C and Ms look more like 390s. The thermostat housing on 351Ws is on the front of the intake like 302s. 351C and M thermostats are on the top of the block.

 

[DJs74]

And in my opinion, if it turns out to be a 351C... grab it! You can go wrong owning a Cleveland... if the motor is actually a C vs. W, you are ahead on the deal. That's just my opinion

DJs74

 

[MikeKC130J]

Thanks for the education tonight hope to have this Windsor by Saturday!

 

[Broncobowsher]

90's would be fuel injected. If it is still all original and together there will be a 5.8 cast into the intake. That is a 351 and that intake won't fit anything else. So easy enough.

 

[Steve83]

'88 was the first year for EFI on the 5.8L in trucks; '87 for the 4.9L; '85 for the 5.0L (all in the smallblock family). I'm not sure about the 7.5L (which is in the M family, and M doesn't actually stand for anything), but I think '88. The Cleveland family wasn't used after '79.

 

[FordBronc]

351C/M/400 335 series: 8 bolts in rectangular valve covers. Timing chain housing is part of block. Thermostat housing on block. Exhaust bolt holes diagonal.

351M/400 335 series: intake is 12.7" wide the 351C is narrow. The 351M and 400 are identical externally, only internal parts examination can tell them apart, or a wooden dowel rod stroke measurement.

351W/302/5.0L 6 bolts on trapezoidal valve covers. Thermostat housing on intake. Exhaust bolt holes horizontal.

429/460 385 series: 7 bolts in rectangular valve cover

352/360/390/427/428 FE series: Intake goes under valve covers.

 

[Broncobowsher]

'88 was the first year for EFI on the 5.8L in trucks; '87 for the 4.9L; '85 for the 5.0L (all in the smallblock family). I'm not sure about the 7.5L (which is in the M family, and M doesn't actually stand for anything), but I think '88. The Cleveland family wasn't used after '79.

5.0 got multiport EFI in trucks in '84. In econolines you could have either the carbureted or EFI 302. I've worked on an '84 EFI F150, parents bought an E150 new.
Cleveland was last used in '73. Only had a 4-year run and only in cars.
351M was used up until about '82. The first couple years of the 80's trucks ran them.
7.5 is the 460 which is a 385 series engine, not an M engine.

Best way I know to tell the difference between a C and an M at a quick glance is to check the bellhousing. C is a small block pattern, M is big block. The big block is very distinct in how far up the upper two bolts are.

 

[ntsqd]

snip...
They are from a different engine family (385 series?)

FYI: The 385 engine family is the 429 and the 460 (I *think* there are also some heavy truck engines of odd displacements (370ci?) in this family too).
The 335 engine family includes the 351's that are not a Windsor and the 400.

As I recall according to the Ganahl book the "M" stands for "Modified" referring to the fact that these are Cleveland-pattern engines but are significantly different from the 2V & 4V Clevelands in the nuances. Whether he is right or not I've no idea.

 

[garberz]

I've always associated the "M" as Midland, from the city the casting plant was located in. Although if you research it, there's no clear answer.

Mark

 

[Steve83]

5.0 got multiport EFI in trucks in '84.

You're the first person who has told me that. I swore I saw an '84 5.0L MFI ~12 years ago in a JY, but all the documentation I've read since then convinced me that it must have been an '85 model built in late '84.

7.5 is the 460 which is a 385 series engine, not an M engine.

I thought I had seen the 460ci/7.5L grouped with the Ms in Haynes, but I see that it's not, so IDK where I got that idea. It uses the same bellhousing pattern as the 6.9L & 7.3L diesels, right?

352/360/390/427/428 FE series: Intake goes under valve covers.

How far under? I don't have a better pic, but this is my uncle's DD:



One of the intake-to-head bolts is barely visible below the plug wires, making it look like the intake is either fully outside, or just barely lipped under the VC.

 

[ntsqd]

I've always associated the "M" as Midland, from the city the casting plant was located in. Although if you research it, there's no clear answer.

Mark

Now that you mention it I've heard & read that too.

About that far, note that the intake ports in the intake are notched on the sides for push-rod clearance:

EDIT: Better pic of an FE intake:

 

[Apogee]

...I thought I had seen the 460ci/7.5L grouped with the Ms in Haynes, but I see that it's not, so IDK where I got that idea. It uses the same bellhousing pattern as the 6.9L & 7.3L diesels, right?

I don't know about the diesels, but the 429/460 has the same bell housing as the 351M/400 so long as you don't count the few 400's that were supplied with the FMX trans and small-block bell housing pattern.

 

[jmangi62]

Doesn't the engine in question have that huge intake on the top of it that sticks up about a foot, and would never fit in a EB unless you have a 12in. body lift and a serious hood scoop? or am I thinking of a different year of engine?

 

[bmc69]

I've always associated the "M" as Midland, from the city the casting plant was located in. Although if you research it, there's no clear answer.

Mark

As a long-time Cleveland builder and fan, I can report that the definitive answer to that age-old question did surface recently: the use of the term 351 "modified" in actual Ford shop technical documentation. I have a pic of the page in question in my archives ...and know the guy that has the source. He has a huge collection of Ford literature.

I was always in the "don't mean nuthin'...it's just a letter they picked" camp myself, and I knew it didn't stand for "Midland".

End of trivia story.

 

[bmc69]

Doesn't the engine in question have that huge intake on the top of it that sticks up about a foot, and would never fit in a EB unless you have a 12in. body lift and a serious hood scoop? or am I thinking of a different year of engine?

That is the typical issue with the pickup and FSB 5.8s for EB use...that monster tall intake.

 

[Seventee]

I always understood the M to mean 'Modified', as in de-stroked 400.

 

[bmc69]

I always understood the M to mean 'Modified', as in de-stroked 400.

That always made sense to me too..but it was probably less than two years ago that I saw proof for the first time that it mean anything at all to Ford..and "modified" it was indeed.