1978 Ford motor question
Freshman User
Joined: Nov 2008
Posts: 30
Likes: 0
You must mean 351m, It is a great engine, but some people have trouble with low oil pressure once it gets over 125,000 miles, but this could be fixed with a high volume oil pump, check out this thread- https://www.ford-trucks.com/forums/7...heir-351m.html
Elder User
Joined: Apr 2006
Posts: 649
Likes: 0
This is the 351M motor. Okay motor, but not if you're looking for a ton of power. Main issues I've had is the dizzy seizes to the block and they only way I've been able to fix this is, take the motor out, heat the block and pound it out. Other 351m motors will last a long time as long as they've been taken care of. The only difference betweent he 351m and the 400 I believe is the crank, so this can easily be converted to a 400. Overall, it should last you a long time. Get us some pictures!
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
You really only have 3 ways to find out. On the valve cover sticker, although it says 351M/400 under family, you should still be able to find actual displacement. Second, if it's the original motor, the VIN will tell you. If those two fail, the only way to tell is to measure the stroke - 3.5" for 351M and 4.0" for 400.
Senior User
Joined: Jul 2008
Posts: 157
Likes: 0
From: Mariposa, CA
If you have the VIN, the fourth digit tells the story. F15S****** OR F15H**** The S indicates a 400, An H indicates a 351M.
RW
RW
You really only have 3 ways to find out. On the valve cover sticker, although it says 351M/400 under family, you should still be able to find actual displacement. Second, if it's the original motor, the VIN will tell you. If those two fail, the only way to tell is to measure the stroke - 3.5" for 351M and 4.0" for 400.
