identifying a 400

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Jul 6, 2000 | 12:02 AM

Superdave

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From: Indiana

identifying a 400

I responed to an add where a fellow has a what he says is a rebuilt 400 for sale. The valve covers say its a 351M. I ask him if they have ever been changed, he says no. The crank dampner is messed up. Its been pulled off with a gear puller I assume and split the dampner where only the center piece is left. How can I be certain what motor this is? I'm not handing him a dime until I can make sure its a 400. I do know it is a 351M or 400 as it has the M stamped on the top corner of the head. Thanks!

Superdave

94 Ford Aerostar XL 3.0L
82 Ford F250 4x4 XLT,400 CID,C-6 A/T,8700lb GVWR. Black & Silver

Jul 6, 2000 | 04:21 AM

Nathan

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identifying a 400

The only wy to know for sure is to check the actual stroke, 400=4", 351=3.5". Ask the seller if he has any reciepts for machine work that proves its a 400 (although proof is only in the writing). If the seller squabbles any about proving actual displacement, leave it alone, its probably a 351.

Nathan

Jul 7, 2000 | 02:00 AM

Superdave

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From: Indiana

identifying a 400

Nathan, I read once (don't remember where) that you could pull a spark plug out and use a small diameter dow rod maybe a foot long or so. Poke the dow rod in to the plug hole, crank the motor by hand till the piston seems to be bottomed out, mark it where its just at the head and bring the piston up to the top of its travel and mark it again and then measure the distance between the marks. I don't know if you could get an accurate enough measurement like this. But I guess it might be worth a try. I could practice on my 400 to see if it works