Okay... so I have this 73 mustang (see gallery) and I decided that because I've owned this car for 3 years, I'm gonna have my local hot-rod shop rebuild the engine. We talked about it and decided to replace the engine because of too many problems with the block. So they go ahead and buy a rebuilt 351 Cleveland (which is what I was told was in the car when I bought it) and pull the other engine out.

Well, come to find out, it was a 351 Modified that was in the car. WTF? So now, they had to find another 351M to put in there. It seems as though the previous owner attempted to rebuild the engine, failed, couldn't find a 351C, so had a 351M dropped in.. which in turn means that the tranny had to be swapped out, motor mounts changed, etc... nothing is what it had seemed when I bought the car.

Now, my reason for posting my saga: What the hell is a 351 Modified? How does it compare to a 351C or W?

Jenn in OH

 

A 351W (Windsor) is the largest cubic inch displacemant small block that Ford built. Same as the 289/302 with a taller deck heigth which allowed for a longer stroke, thus giving you more cubic inch.
A 351 M (Modified) and a 351 Cleveland are both big blocks.
If memory serves me right, the Modified and the Cleveland both should use the same motor mounts, and transmission flex plates.
I know a standard C-6 transmission will bolt to both the M and the C, but you need a special C-6 to bolt to the W.
Hope this helps.

 

Sorry to hear about your problems, now prepare to get .

The 351 Windsor was the original 351 from Ford. It was a good engine that was suited to higher rpm and worked nice in medium-sized cars. Power was ample, but it didn't fit the bill for the "muscle-car" war that was going on in the late 60s. Ford redesigned the 351 so it would produce both good low end, and have decent hp; and the 351 Cleveland was born. It was the muscle car 351 with a great power band all the way to an awsome 6500 rpm. The 351C was available from about 1969 to 73-74, when government pollution restrictions and MPG requirements forced Ford to "wuss-out" the 351C with EGR valves, cat converters, and a modified bell housing so it would mate to newer MPG improving transmissions. The 351 M (sometimes called Michigan) meaning Modified was born.

The short answer (too late) is that you lost a late build 351C to a wussed-out 351M. Sort of like trading your diamond ring for a cubic zirconia; looks the same-but isn't.

 

Jenn,

Check out http://www.vintage-mustang.com/
Their forum is set up a little different but they can tell you a lot about your car and offer a lot of truly great advice. I cannot recomend those guys enough.

Stan

 

PBCrisis - Thanks! I just registered over there.

Jenn in OH

 

PBCrisis - Holy cow! I posted my question, and like 5 minutes later, I had 4 responses... Even someone from MY neck of the woods...

Seems as though I won't be too disappointed with it as long as it's a good rebuild (which I'm pretty sure it will be).

Thanks again for the link.

Jenn in OH

 

it seems to me that the cleveland uses the 351 W 302 289 bellhousing (roughly 7 inches on the top bolt spread), while the Modified uses the bigblock 429 460 bellhousing (something like 11 inches on the top bolt spread) The heads on it are a toned down cleveland 2v head with slightly smaller valves, and ir seems to me the m uses the 400 M taller engine block and longer rods. The crank is a 3.5" stroke like the cleveland but uses a .25" larger main bearing. The nice 4v heads or aussie 2v heads (both quenched chamber) will directly bolt onto your block but the intake is diffrent because of the extra block height. You can build one up like a cleveland but there just isn't any aftermarket support for it. I use the cleveland in my 73, but I do have an M drivetrain (engine and fmx tranny) just in case. Hope this helps

 

Told ya

Stan

 

Marc,
Wasn't there a Ford tranny called an FMX that
would bolt up to the W? I vaguely remember
something to that effect...but wouldn't swear by
it though.

 

yes there is, the bellhousing on the fmx is detachable like those found on manuel trannies. And the smaller bolt pattern will bolt up to the W engine.

 

I thought so...I remember taking an FMX out of an
late 70s LTD at a junkyard (which had a 351 W)
and putting it in a 79 pickup. Man, that was a LONG
time ago...I'm making myself feel really old.