351W vs. 351M

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Mar 25, 2001 | 04:10 PM

gbashjr

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351W vs. 351M

I've got a '78 Bronco w/a 351M. I've been looking for a parts trucks and I've found one that I've been told has a 351W in it. This leads me to the question at hand. What is the difference between a 351W and a 351M and is there any visual ways to tell the difference?

Thanks a bunch for the info!!!!

Mar 25, 2001 | 05:29 PM

ecarter50

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351W vs. 351M

351w and 351m are totally different engines about the only thing they share is cid. the 351w has 6 valve cover bolts the 351m has 8

Mar 25, 2001 | 05:57 PM

Bill_Beyer

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From: PacNW

351W vs. 351M

The 351M and 351W are different families of engines however they share a little more than CID. They also have the same bore spacing and diameter so with some minor modifications the heads can even be interchanged. M heads are identical to 2V Cleveland heads and have larger valves than the W. The 351M has a much taller block than the W and is a much heavier engine. It also has the same bellhousing bolt pattern as the 385 series (429/460) while the W has the same as a 289/302. As was stated the 351M has 8 bolts per valve cover while the W has 6. The M also has a "dry intake" so the thermostat housing goes into the block instead of the intake manifold like the W.

Apr 11, 2001 | 03:26 PM

magnus

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From: Renfrew Canada

351W vs. 351M

the windsor is the better motor, but a conversion would not be worth your while, since as stated above, the bellhousing will not bolt up. But if you are looking for more power, who isn't, drop in a 400. not much of a rever (4" stroke), but gobs of torque, and most cleveland goodies fit.

If you didn't build it, its not really yours.

Apr 13, 2001 | 06:06 AM

84w44s

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351W vs. 351M

>the windsor is the better motor,

i agree 100%

But
>if you are looking for
>more power, who isn't, drop
>in a 400.

if your gonna invest time and money in a swap, drop in a 460. more aftermarket parts available, don't have to do as much to liven it up, and you get a big block.

Apr 17, 2001 | 10:09 PM

magnus

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From: Renfrew Canada

351W vs. 351M

you're right 84w44s, swapped a 400 for a 460 in my 79 F250

If you didn't build it, its not really yours.

Jul 19, 2001 | 10:21 AM

ryanstruck

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351W vs. 351M

Windsor is a great motor-I got one in my 86 F250 HD with a holley 750 4bbl and an edelbrock 351W Performer Intake. Lots of power. Hey, it's the original choice of the lightning before the 5.4 Triton

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Jul 19, 2001 | 10:28 AM

ryanstruck

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351W vs. 351M

Question, now that I think of it. In the engine compartment, there is a sticker under the hood that says "non-catalyst". Does this mean the truck doesn't require cats? It would help alot cause it doesnt have em, doesnt have the emisions module...heck it has no emisions whatsoever, so suffice to say it would never pass inspection. Also, how hard is it to change the oil pan gasket? Do you have to lift the engine off the mounts to get around the frame cross member? Can you just lower the pan enough and play around to get the gasket on? I just dont have the time to lift the engine up just to get to the oil pan.
This has been a great forum though. I originally thought that the 351W and 351C just refered to the location of the plant they were manufactured at and the 351M was just a modified version. Thanks alot fellas.

Ryan
1986 F250 HD 4x4
351W Holley 750 4bbl
Edelbrock 351W Performer Aluminum Intake
Flowmaster Stage III Exhaust