351M / 400 Crank Swap

I read in one of the ford muscle article about taking a 400 crank and putting it into a 351M. Is this really just converting to a 400? Do I need to use the 400 rods with the swap or re-use the 351M rods? What if any other mods should I do to get the max grunt out of the 351M? My use for the motor is in a stock racing class on a oval track. The motor currently twists about 5,000 rpm's. Any help that i could get on stroking and grunting this 351M would be greatly appreciated.

Well, basically you'd be just converting it into a 400. I think it would be more simple and less costly to just get a complete 400 and bolt it in.

Hi.. You need a 400 crank & 400 pistons.. you can use your 351 rods.. All else is the same >>>Jim>>>>fordsemi

What you need to do is I take it you are talking about a 351 windsor block? If so get a 400 midi crank, get the main bearing journals ground to the same size as the windsor crank. Then grind the webs down so as to get the crank to physically fit into the block and rotate. You will have to re-balance the crankshaft with mallory metal or "heavy metal" to off set the weight you have removed. (Still with me) You can then use 6 inch Carillo or similar chev con rods and increase the bore size to 4 and 1/8th (or 4 and a 1/4 if you can get a SVO block.) This will give you a very srong torquey donk the will be between 383 cubes and 454 cubes depending on bore size. And believe me this is a gem of an idea for cheap horse power and more importantly torque. Don't muck around with anything else just do this and you'll think all your Christmas's have come at once!
CheeRS, Skid.

Basically the 351M is a 400 with a 351 W crank

Bless you Skid!


Good eye der, converting a 351m into a 400, if they check the casting numbers they will know right away, but if they don't you'll have a mule in horse's game and we all know that mules out work horses. Now get out there and kick some butt!

Increasing the bore size will make about 408 cubic inches, you shouldn't have anyproblems with the 2V heads to make 400 hores and 400 plus foot pounds of torque. The 5000 rpm range is perfect for the 400 cube Modified block and crank.

Make sure your gearing is right, and that you get a good ignition aftermark if possible. The 650 cfm holley work well on this combination. Edelbrocks website shows the 400m with good numbers in the 330-350 hp range with 385 foot pounds of torque. Just make a good cam selection. Call the boys at Cam research, they can set you up with a good cam.

Mac

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i am grinding a 351M crank to fit in a W351 4 bolt block. Cutting .125 off throws to clear lower cylinder walls. block will be 4.125 bore. planning on being a 454 small block. if it runs good will ad a T76 garrett turbo. going in 95 stang/ Pony hasn't run in awhile hope to make it get up and go

a 351M is a 400,the 351W crank has a 3.500 stroke the 400/351M is 4.000 stroke 351M stroke is 1/2 inch longer than a 351W mains and rod journals are the same 2.310 on the rods and 3.000 on the mains

cut .200 of counter weights 351M crank will fit in 351W block w/ a little grinding on block besides clearancing for the rods. just finished grinding one last night and tried it out in the block turns good/ now got to fit everything. find got to find the right rod for the extra 1/2 inch stroke

<font size=-1>[ This Message was edited by: crankshaft on 1/25/05 7:28am ]</font>

Don't think you can offset grind a 351M crank to a 4.24 stroke. [img]/phpBB/images/smiles/icon_confused.gif[/img]
[addsig]

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On 2005-01-22 21:59, crankshaft wrote:
a 351M is a 400,the 351W crank has a 3.500 stroke the 400/351M is 4.000 stroke 351M stroke is 1/2 inch longer than a 351W mains and rod journals are the same 2.310 on the rods and 3.000 on the mains
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If I read that right, you are saying that the 351M and 400 are both 4.000" stroke, correct? WRONG. 351M 3.5" stroke. 400 4.000" stroke, both use 4.002" bore but the 400 uses different pistons...same rods as 351M (6.58&amp;quot[img]/phpBB/images/smiles/icon_wink.gif[/img]

the 351W and 351M have exactly the same bore/stroke dimensions. The W has shorter rods and a much shorter deck (9.5" vs. 10.22&amp;quot[img]/phpBB/images/smiles/icon_wink.gif[/img] The main journals are both 3" dia.

Also, if you are using a 351M crank in a 351W block, it will be 363 cubic inches. Use a 400 (4.000" stroke) crank and it'll be 415". I don't think I'd trust a ground-down cast crank in a turbocharged motor. Been there, done that....learned a few expensive lessons along the way!

<font size=-1>[ This Message was edited by: mavman on 1/25/05 8:37am ]</font>

<font size=-1>[ This Message was edited by: mavman on 1/25/05 8:40am ]</font>