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factory/modified?????
#1
trying to find what factory/ modified is all about for 73 351C
Huh
  Reply
#2
Who told you?
Why did they say it is "factory modified?"
What did they back their reasoning up with?
What is stamped on the engine?
What is your VIN?

-Kurt

[Image: satellite-valiant-mustang-license-tags-signature.png]
How to buy a '71-73 Mustang:
Rule #1: Assume all classic car sellers are guilty until proven innocent.
Rule #2: No classic car dealer is ever innocent; thus, they are all guilty.
Rule #3: Buy from trustworthy people: Fellow forum members. Visit 7173Mustang's For Sale forum.
  Reply
#3
cudak888;163498 Wrote:Who told you?
Why did they say it is "factory modified?"
What did they back their reasoning up with?
What is stamped on the engine?
What is your VIN?

-Kurt

{thumbs up} all of the above...Good way to check is if you have a 2 or a 4 stamped on the front of your heads too...Atleast that will tell you if you have cleveland heads or modified.. modified heads can be stuck on a cleveland and trick people into thinking it is a modified..But some not knowing any better will say its a modified cause they are almost the same from the top view...But most will not put the modified block in a mustang cause it needs a bigger bell for the trans.
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#4
you could very well have a 351M the ugly twin to the 400M.

Anything is possible, It just takes time and MONEY....
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#5
The M engines have a higher deck i believe. You should be able to find some numbers that would help.
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#6
I suspect whoever told you that is not quite as familiar with Ford engines as they think they are.
In 71-73 Mustangs, any car with a 351 engine is a "Cleveland". There were 2V (2 barrell) versions and several versions of the 4V (4 barrell). There were no 351 "Windsors" installed in any 71-73 Mustang/ Cougars...no matter what anyone tells you. ( except for Mexico-built Mustangs...apparently they used "Windsors" in those)

The 351 "M" and the 400 were both later-year variations on the "Cleveland" but these were never installed in any Mustang.
There was even a "351/400" engine, not too sure what the difference was in that. I had one in a '79 Lincoln MK-V. It was terrible, no power at all...but at least it used a ton of gas!
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#7
Welcome to the forum!

It is very unlikely that your Mustang has a 351M. It would be a transplant and they would have to replace the transmission as well. A VIN will help us know what is the original engine. It is not unlikely that something else was swapped in over the past 40 years but usually it would be a small block variant such as a 302/351w or a 351c.

Some pictures would help a lot too.

You have found a great place for all kinds of info on your mustang, from 'original' to 'what will work'. Welcome to the club!

'Mike'
73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
  Reply
#8
I'm thinking it may be a factory M code engine...
  Reply
#9
Kit Sullivan;163538 Wrote:There was even a "351/400" engine, not too sure what the difference was in that. I had one in a '79 Lincoln MK-V. It was terrible, no power at all...but at least it used a ton of gas!

No difference, there never was such a thing. Ford made the ID tag for the LH valve cover with both engine family names on it ("351M/400"), hence the confusion.

All 335-based blocks in the Lincoln Mark V were 400's, including the CA and special order 400's made in 1977. Same applies for the 4-door and 2-door Continentals.

No one has since reported taking one apart and finding a Windsor crankshaft and the taller pistons of the 351M, so unless someone swapped the block on one of these (or someone discovers one of Ford's infamous substitutions), they're all 400's in the Lincolns.

will e;163554 Wrote:It is very unlikely that your Mustang has a 351M. It would be a transplant and they would have to replace the transmission as well.

Not true. Though most 351M/400s came primarily with the big block bellhousing pattern, 1973 editions of the block came cast with both patterns and starter holes for the small-block transmission bellhousing.

[Image: odd400.jpg]

The 351M/400 generally has different engine mount drillings as well, but I believe the 351C mounting locations are available to drill out.

Funny - nobody has taken the above opportunity to build a 400C. Too much work when the 460 is around, I assume.

That, and "400C" sounds like a Chrysler luxury barge.

-Kurt

[Image: satellite-valiant-mustang-license-tags-signature.png]
How to buy a '71-73 Mustang:
Rule #1: Assume all classic car sellers are guilty until proven innocent.
Rule #2: No classic car dealer is ever innocent; thus, they are all guilty.
Rule #3: Buy from trustworthy people: Fellow forum members. Visit 7173Mustang's For Sale forum.
  Reply
#10
Same decal, both engines. Now it all makes sense!


I have had a couple 351Ms over the years and some 400s too...none to impressed by any of them. I seem to remember reading somewhere that Ford's goal with these was to make a low-end torquey, emissions-friendly powerplant out of the outdated "Cleveland" technology.
I would not consider any of those engines "torquey", and they were all gas-guzzlers. My 78 460 MK-V was much more torquey and got better mileage (14) than my 78 400 MK-V (12).
The mid/late 70s 460s were embarrasingly down on power, but they still felt good down low...plenty of "stop light" torgue available. Too bad it all fell off above 30 mph or so.
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