I recently purchased a 1979 F150 as a wheeling rig, and have been unable to determine whether it's a 351w, 351c, or 351m. Are there any distinguishing features which would help determine? I looked for some sort of vin tag on the engine, but it had recently been rebuilt, and no markings were visible.
Picture:
http://www.omedcalifornia.org/images/f150/EngineFront.JPG

Thanks in advance :smokin:

Going way back in my memory (burnt brain cells). The Windsor had horizontal fuel pump mounting bolt pattern and the Cleveland/Modified had veritcal mounting bolt pattern. Also the t-stat housing mounts vertical on the Windsor and horizontal on the Cleveland/Modified. From what I can tell you have a Windsor but the aftermarket manifold could make it different.

Thats a 351c or 351m, I'd say it looks like an origional And thats an M. Check the casting number on the block above the starter If it starts with D9OE it's a 351m or C9OE or DOOE and such it's a 351C, I think they quit making the C around 71-72. The M wasn't in production till around 75 I believe

thats a 351m/400 if its the stock motor or came from another truck its not going to be a 351c, cause they weren't offered in a truck (unless you count the rancheros), the 351m/400 will have a dry intake manifold so if the thermistat housing is on the block its definately a 351m/400, windsors had it in the manifold.

stick a screwdriver down the spark plug hole and measure that to see if its a 400 or a 351

FYI, the 351C and 351W use the same bellhousing pattern as the 302. The 351/400M use the 429/460 bellhousing bolt pattern.

The C motor was never installed factory in trucks. The C and M motors have flat stamped steel timing covers. The W has a timing cover similar to a SBC.

That IS NOT a 351W. If it was, the valve covers would look like 302s, longer along the bottom edge, tapered in at the top.

measure the top 2 tranny bolts from center to center. i have a spare bigblock tranny from a 351m and if the measurements are the same its a 351m/400 if smaller its the 351c i have a cleveland and a 351m in my garage and from the side they look the same but the m is alot wider

here is our 400 we are selling.. same body style truck, factory motor...

http://i54.photobucket.com/albums/g103/Adamovol/007-2.jpg

dunno if it helps, but it seems the same width as the 351.... hard to tell....

The 351/400M use the same casting, so width is the same.

An easy to identify on the Fords is to count the number of retaining bolts on the valve covers. This should be the same for cars and trucks.


5 bolts = FE Block
6 bolts = 289/ 302/ 351Windsor
8 bolts = Cleveland / Modified

You can reference this as well:

2 bolts the engine is a: 239/256/272/292/312 (produced from 1954 to 1964)
5 bolts the engine is a: 332/352/360/361/390/391/406/410/427/428/ (FE engine)
6 bolts the engine is a: 221/260/289/302/351W
7 bolts the engine is a: 429/460
8 bolts the engine is a: 351C/351M/400

It's an M

And the first thing I would do is throw that carb in the trash..

Does the motor have any recipts of what went in it?

There are other ways of identifing the difference between a 302/351W, and a 351C/351M/400.

The 351W and 351M/400 both have wider intake areas than their smaller brothers. I don't remember an exact number, but I do know they are about 2" wider. This is because the motors have a taller deck height to accomodate a longer stroke.

*most* 2 barrel Clevland heads(also used on the 351M/400) will have a 2 cast into the upper corner, right below the valve cover sealing area, 4 barrel heads will have a #4 cast in the same position.

A 351W will also have a rib on the block between the top of the belhousing (top two bolts) and the lower intake sealing surface.

A 351C will have a sub 5" distance between the top belhousing bolts, same as the late 302/351W. The 351M/400 will have about 7" between the top bolts, just like a 460. NO, that does not make that motor a big block, it only shares the pattern, and distributor with a big block.

The 400 started production in '71.

The 351C production ended in '74, a 400 was destroked to 351 to take its place. The 351M/400 was terminated in '79 in cars, and 82 in trucks IRC.

Certain 351M/400 cast before 1977 had problems with cracking in the lifter valley. I dont have the casting number handy, but it was only blocks cast at a certain foundry that are affected. If anyone cares, I will look it up.

Certain rare '72 400 blocks have both belhousing patterns, for big blocks, and small blocks.

351M/400. Pull a plug and measure the stroke. Hope it's 4".