351m
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From: Rocky Point, North Carol
351m
I have a question. I thought that 351m's and 400's were identical externally. I have an unknown year 351m I am using for parts, and a 76 model 400 that I am putting in my 77 F150. I found out (the hard way) that the bell housing pattern for the 400 is larger than that of the 351. I have also noticed a few more subtle differences. (thermostat housing, distributor size, throttle linkage, etc.) Are these differences just because of the year they were made, or have I misunderstood what I was told about the two engines? I have also noticed two or three distinctly different styles of engine mounts between the 2 motors. Am I in for any more surprises?
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Joined: Jun 2003
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From: WA
Are you sure you have a 351M and not a 351W? Easy way to tell is look at the valve covers. The 351M and 400 block are identical.
From a different thread:
351C/M/400 335 series: 8 bolts in rectangular valve covers. Timing chain housing is part of block. Thermostat housing on block. exhaust bolt holes diagonal.
351M/400 335 series: intake is 10.7" wide the 351c is narrow.
351W/302/5.0L 6 bolts on trapezoidal valve covers. Thermostat housing on intake. Exhaust bolt holes horizontal.
429/460 385 series: 7 bolts in rectangular valve cover
352/360/390/427/428 FE series: Intake goes under valve covers.
From a different thread:
351C/M/400 335 series: 8 bolts in rectangular valve covers. Timing chain housing is part of block. Thermostat housing on block. exhaust bolt holes diagonal.
351M/400 335 series: intake is 10.7" wide the 351c is narrow.
351W/302/5.0L 6 bolts on trapezoidal valve covers. Thermostat housing on intake. Exhaust bolt holes horizontal.
429/460 385 series: 7 bolts in rectangular valve cover
352/360/390/427/428 FE series: Intake goes under valve covers.
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From: Rocky Point, North Carol
i dunno
The original engine from the truck which was a 351m has the valve covers and gooseneck like you described, but when I went to put the 76' 400 in, the bell housing for the same manual trans was too small. My friend had a bell housing laying around that mated the 400 and the trans just fine. I had to use motor mounts from a 76' ford truck with a 400, the ones from all other years would not fit. Could it be that I have a set of 351m heads on a "c" or "w" block?
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From: chicago burbs
if the "thermostat housing, distributor size, throttle linkage, etc." are different, then it can't be a Cleveland. those are all the same to a 400. i think you need to look at the timing covers, fuel pump mounting bolts and exhaust manifold bolt pattern.
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From: Rocky Point, North Carol
I am going to pull the numbers off the block tomorrow so that I can check that way and know for sure.
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From: Rocky Point, North Carol
Ahhh, I misunderstood what you all were trying to tell me before. I checked back over the thread and realized that the 8 bolt covers applied to the "c" engine as well.
<!Well, I am trying to get rid of the motor and another 400, plus the accessories for both.> <! I put an add in the classifieds.> <! I am trying to trade both for some other> <!fo rd parts for my truck.>
(Now I know why the new rod bearings wouldn't work.) I really feel like an idiot. Once again, thanks for all of your help Bill.
<!Well, I am trying to get rid of the motor and another 400, plus the accessories for both.> <! I put an add in the classifieds.> <! I am trying to trade both for some other> <!fo rd parts for my truck.>
(Now I know why the new rod bearings wouldn't work.) I really feel like an idiot. Once again, thanks for all of your help Bill.
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From: Rocky Point, North Carol
I just updated my gallery to include the pics of the new 400 going in. Check it out if you would like. It took some interesting mods to get the cluitch linkage right. Here it is:
https://www.ford-trucks.com/user_gal...&albumid=12355
https://www.ford-trucks.com/user_gal...&albumid=12355
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The Diffrence Between the 351m and 400 is the Crankshaft and pistons. The 351m has a 4.00 inch bore, and a 3.5 inch stroke. A 400 has a 4.00 inch bore, and a 4.00 inch stroke. Everything else is interchanegable. The M block's are bigger so they can hook up to the same tranny as the 460.
- Valley width ( intake ) is larger than any of the other 335 series at 10.7"
- The M blocks valve covers have a raised point for the oil cap.
An by the way, the 351m-400's are great engines. I got a 400 in my 78 F-150 Supercab. I got the truck for free from a friend of mine, ( which im rebuilding ) that was sitting in a field for 7 years. I put a battery in it, cranked it over 5 times, and it fired right up, and i drove it right out of the field, got a permit, and drove it 20 miles home. I have had that truck for a year now, and ive drove it lots off road, and it hasent given me any trouble.
Good luck on your 400
- Valley width ( intake ) is larger than any of the other 335 series at 10.7"
- The M blocks valve covers have a raised point for the oil cap.
An by the way, the 351m-400's are great engines. I got a 400 in my 78 F-150 Supercab. I got the truck for free from a friend of mine, ( which im rebuilding ) that was sitting in a field for 7 years. I put a battery in it, cranked it over 5 times, and it fired right up, and i drove it right out of the field, got a permit, and drove it 20 miles home. I have had that truck for a year now, and ive drove it lots off road, and it hasent given me any trouble.
Good luck on your 400