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Discussion Starter #1
hi guys im redoing a 351c [ford motor]need all the help i get somwhere i saw were i can put a 400m crank in her please help with anyting may god bless gordon :p
 

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Gordon, point your internet browser at "Google.com". Enter "351 Ford", press enter, and stand back - all the information you need to complete your project will magically appear!
 

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351c crank dimensions are:
3.50 stroke
rod bearing shaft dia. 2.3103 to 2.3111
rod bearing clearence .0008 to .0026
main bearing shaft dia. 2.9994 to 3.0002
main bearing clearence .0013 to .0029
end play .004 to .008

400m cranks are :
4.00 stroke
rod brg shaft dia. 2.3103 to 2.3111
rod brg clearence .0008 to .0026
main brg shaft dia. 2.9994 to 3.0002
main brg clearence .0009 to .0026
end play .004 to .008they should interchange easily
thrust brg position is #3 main cap for both cranks
this is for 70-73 clevelands and 72-74 400 m
75-81 400m is a little bigger on rod brg shaft dia and main brg shaft dia
hope this is what you wanted
 

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Are you sure you want to put a cast 400M crank in where a forged 351C crank sits and get rid of the heavy duty 351C rods. To put this crank in you would need extra short aftermarket rods to fit your new cast crank. I don't know of anyone who makes this type of rod because the 351M/400M motors had a 1" higher deck height. There is a minimum rod length to stroke ratio beyond which the rod will exert excessive side thrust on the crank and pistons. This is one reason why longer rods are better and it also lengthens the piston dwell time at TDC. I don't know of any pistons made to accomplish this swap using even the short weak 400m rods, are there?

You could use a 351M crank with your 351C rods but you would have one problem. The larger rod side clearance needed for the forged crank (it has a higher expansion rate because it is a forging) means your 351C rods would not have the correct side clearance and would be too narrow since the clearance is ground off the rod width, this would lead to oil pressure loss because of the excessive clearance. You could solve this by welding up the crank journals and regrinding them but then you still only have a cast crank.

This is why this kind of swap is never done with 351C engines. Although the journal sizes are the same there are other mitigating factors that prevent the swap from being realistic or desirable.

I might be wrong!, is there a company that makes the special pistons and rods necessary to do this kind of swap? I have been in the garage for a while!

The only blurb I could find when I searched was this statement;
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"[email protected] (Dave Williams)
detomaso 06 Apr 1998
- -> There were a couple of stroker engine builders displaying there
-> stuff. One had a 438 inch 351C package consisting of a modified 400
-> crank, aftermarket rods, and 0.040" over custom pistons. He claims
-> the whole thing will fit in a 351C block.
- Wow. That takes a 4.275 stroke, which would take something on the order of
a 2.0" small journal Chevy rod, .030 undersize. That's about as far as you
can go without a custom or welded crank. "
--------------------------------------------------

Has anyone seen this stroker kit?
 

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Correction,

After doing some digging I found out only 351 SCJ cranks are forged, CJ and 2bbl cranks are grey nodular iron which is still plenty strong and tough.
 

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Actually none of the Cleveland cranks were forged, High nodular iron like the 428CJ, that's why Glidden always had special Moldex cranks. Check out Speedomotive they offer plenty of stroker kits for the Cleveland. Make sure you have a cleveland instead of an M, a 400 crank and rods will drop right in an M,'73 was the last year for the Cleveland they were M's after that.
 

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aka Duke of URL
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  • There is (was) no 400M...The 351M designation is to differentiate this engine from the 351C/351W...
  • There was no 351 SCJ...351 BOSS/HO/CJ/4V/2V
  • All cranks (incl 351 BOSS) were nodular iron...
  • Last year of 351C production was 1974...
  • The 351M was introduced in the 1975 model run...
 

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The 400 crank mains are 2.999 compared to 2.749 on the 351C other wise except for the 1/2" stroke they are the same.
 

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aka Duke of URL
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If you really want a 400ci. Cleveland, it would be easier to start with a 351M/400 and go from there. Earlier Cleveland heads can be used and there are spacers available to use the earlier intake manifolds.

In a way, you are just making extra work/expense for yourself.
 
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