351M/400 difference
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Junior User
Joined: Dec 2012
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351M/400 difference
I have a 77 F250 4x4 and when I bought it the guy told me it had a 400 the vin says 351M. I know there's not any huge difference between the two I'm just curious as to what motor exactly I have (if the 351M was swapped out) and if there were any easy ways to tell.
More Turbo
Joined: Jan 2008
Posts: 628
Likes: 3
From: in the middle of nowhere
4" stroke is a 400. I still like the antenna mast idea, may work on the clevland style head. Mike, aren't the cam specs different too? I know that doesn't help to I.d. the motor but that thought is lingering in my head.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Not sure about the cam specs.
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Post Fiend
Joined: May 2012
Posts: 14,724
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From: Gods Country, Kansas
By looking at the hole in the crank pin and compare it to the location it is to the main and the radius seam, you can see the difference in a 351M and 400.
400 Casting numbers:5M, 5MA, 5MAB, 5MABC
400 Casting numbers:5M, 5MA, 5MAB, 5MABC
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shane_lxi
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
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Nov 15, 2013 11:05 AM