351C or 351M?
New User
Joined: Mar 2002
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351C or 351M?
I am new here and was wondering how to tell the diffrence betweena 351C and a 351M. I have the chance to get what I was told is a 351C from a 1975 Torino Wagon. The engine is still in the car. Also will this engine bolt to my 1984 Bronco. I currently have a 1970 302 with a C6 transmission in it. Any info would be greatly appreciated.
Posting Guru
Joined: Aug 2000
Posts: 2,416
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From: PacNW
351C or 351M?
I would be very surprised if it was a 351C if it's original. They quit making the Cleveland in 1974. The 351M was introduced in 1975 to take it's place. The 400 as well as the 351M were installed in larger cars and trucks. If it is a 351C then it should bolt up to the existing transmission in your '84. If it's an M then you will need a trans with the larger bolt pattern of the 429/460.
Since the 351M/400 block has over an inch taller deck height, the easiest way to tell the difference is the to look for a large 3/4" wide ridge of metal just to the left (driver's side) of the t-stat housing on the top front of the block that runs from front to back. The most definitive way to tell is to look at the casting code on the block which is below the right (passenger's side) bank of cylinders near the back of the motor. A DOAx or D2Ax will be a Cleveland. A D1Ax, D4Ax, D5Ax, D7Tx or D8Ax will be an M. A D3Ax would mean it's a 400 with the FMX or Cleveland bolt pattern which means it would still bolt up to your existing trans.
Since the 351M/400 block has over an inch taller deck height, the easiest way to tell the difference is the to look for a large 3/4" wide ridge of metal just to the left (driver's side) of the t-stat housing on the top front of the block that runs from front to back. The most definitive way to tell is to look at the casting code on the block which is below the right (passenger's side) bank of cylinders near the back of the motor. A DOAx or D2Ax will be a Cleveland. A D1Ax, D4Ax, D5Ax, D7Tx or D8Ax will be an M. A D3Ax would mean it's a 400 with the FMX or Cleveland bolt pattern which means it would still bolt up to your existing trans.
