Help 351/400 crank

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Aug 16, 2001 | 11:30 AM

Irondale90

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Help 351/400 crank

Can the 351M crank be changed out with a 400 without changing the connecting rods? Any help please

Aug 16, 2001 | 11:52 AM

beartracks

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From: Albuquerque

Help 351/400 crank

I believe the rods are the same but crank "and" pistons are different.

1977 Ford F-100
400m/c6/4:11/Gear Vender O.D.
Crane hydralic roller, forged, ported polished,Deamon,Edlebrock, yada, yada, yada
280,000 miles
Stock on the outside
modified/rebuilt everything

Aug 16, 2001 | 12:30 PM

Bill_Beyer

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From: PacNW

Help 351/400 crank

Rods are identical but you must use 400 pistons also.

Aug 16, 2001 | 03:05 PM

Irondale90

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Help 351/400 crank

So the 351M pistons are taller, mounted higher or something like that?

Aug 16, 2001 | 03:16 PM

Bill_Beyer

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From: PacNW

Help 351/400 crank

Quote:

So the 351M pistons are taller, mounted higher or something like that?

Yes they have a taller compression height than the 400 pistons. If you were to try to use them with a 400 crank they would hit the head at TDC.

Aug 16, 2001 | 03:29 PM

Irondale90

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Help 351/400 crank

[font size="1" color="#FF0000"]LAST EDITED ON 16-Aug-01 AT 04:31 PM (EST)[/font][p]So would it be more worth while to convert my 400m or rebuild a 390 FE I have a C-6 to bolt to the 390 but i have to change out the output shaft to convert to four wheel drive.

Aug 16, 2001 | 03:53 PM

Bill_Beyer

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From: PacNW

Help 351/400 crank

Quote:

So would it be more worth while to convert my 400m or rebuild a 390 FE I have a C-6 to bolt to the 390 but i have to change out the output shaft to convert to four wheel drive.

It would be a whole lot easier and cheaper to convert your 351M to a 400 (no M) since there's no engineering or tranny swapping to do but it's your call. In your case where you have to rebuild an engine anyway and rebuild the tranny I'd stick with the 400...