351 durability
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Senior User
Joined: Jan 2006
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From: Little Falls,New York
351 durability
Hi, I'm new on this forum,usually over in the FE's.I have an opportunity to pick up a 351 in great shape(specs wise),but have heard alot of bad things about them self destructing.Its a 77 truck engine,still 2v.An Edel performer comes with it-4v.Would it be a smart choice to pick this up and run it,or should I go with the ol' trusty FE?
Cargo Master
Joined: Dec 2004
Posts: 2,232
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From: NE Texas
Is it a 351W or a 351M? Actually I've never thought of either of them to be anything less than durable.
I don't know what "they" say about the durability of them, but it sounds like anecdotal evidence. I've heard people complain about a particular truck or car or engine or whatever to be no good. When you start asking questions or learn more you often find that they didn't take care of it to begin with. Even if something is taken care of, all the makers get a lemon out the door from time to time.
What are you wanting to do with the truck that makes you think that it won't hold up?
BTW, I've been driving and working on Fords for 40 years and I've probably had more grief with FE's than anything else. I love the FE's but they do have their peculiarities.
I don't know what "they" say about the durability of them, but it sounds like anecdotal evidence. I've heard people complain about a particular truck or car or engine or whatever to be no good. When you start asking questions or learn more you often find that they didn't take care of it to begin with. Even if something is taken care of, all the makers get a lemon out the door from time to time.
What are you wanting to do with the truck that makes you think that it won't hold up?
BTW, I've been driving and working on Fords for 40 years and I've probably had more grief with FE's than anything else. I love the FE's but they do have their peculiarities.
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Senior User
Joined: Jan 2006
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From: Little Falls,New York
Sorry.the engine is a 351 M.It is going in a falcon.I have heard from many people that the M engines self destruct notoriously.I personally have never had any experience with them,but it seems like all the Ford guys I know that have dealt with them swear dead against them.Not everyone agrees though... .But there must be some kind of reasoning behind all of that.Do the 1977 truck engines have any known defects?It is a smog engine I believe.
Post Fiend
Joined: Aug 2008
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From: Sin City
The 351m will really wake up with the 400 crank and pistons. This is a fairly inexpensive upgrade. Yes it is a smog motor and a cam will be a big help. Do a search on 351m to 400, lots of info on this rebuild.
I'll have the Roast Duck
Joined: Jul 2002
Posts: 9,622
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From: Northshore, MN
only some early blocks had cracking issues from the Michigan casting plant. The 77 and newer blocks should have a D7TE casting number and these have a thicker web for one of the center main caps, IIRC. Anyway, these engines not being durable is a myth. Yeah some will pop a rear main seal relatively early on, but the same arguement can be said about FE's and their intakes/valve covers always leaking. But as was said, each has their own bellhousing bolt pattern, and neither one of them will fit easily into a Falcon....unless you do the Mustang II swap and cut out the shock towers.
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Cargo Master
Joined: Dec 2004
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From: NE Texas
Yes I had forgotten about the casting problem. There were indeed casting problelms with blocks cast in the Michigan Casting Center before March 2, 1977 are the ones to worry about.
If it was cast in the Michigan Casting Center you will find a logo at the top rear of the block behind the intake manifold that has a wide M above a large C. If it has that and the casting date which is next to it is March 2, 77 or earlier it is prone to the problem.
Other than that cracking problem, there are just no weaknesses in these engines. Build it properly, drive it reasonably and take care of it and it will serve you as well or better than anything.
If it was cast in the Michigan Casting Center you will find a logo at the top rear of the block behind the intake manifold that has a wide M above a large C. If it has that and the casting date which is next to it is March 2, 77 or earlier it is prone to the problem.
Other than that cracking problem, there are just no weaknesses in these engines. Build it properly, drive it reasonably and take care of it and it will serve you as well or better than anything.
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I'll have the Roast Duck
Joined: Jul 2002
Posts: 9,622
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From: Northshore, MN
400 (no M) is even better. Heck, I'd just give the 400 and 4v intake to me and we'll call it good, lol.
all the same info applies, except the 400 is better with it's longer stroke (yes it is even longer than a 460) FWIW, I'm putting a 400 (eventual 434) into my 1987 Tbird for reasons I could go on forever about....it's just taking me longer than hoped for with other life issues and all. Good luck in yours.
all the same info applies, except the 400 is better with it's longer stroke (yes it is even longer than a 460) FWIW, I'm putting a 400 (eventual 434) into my 1987 Tbird for reasons I could go on forever about....it's just taking me longer than hoped for with other life issues and all. Good luck in yours.
Elder User
Joined: Oct 2007
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Ive seen alot of 351Ms last a long time in trucks that looked like they were falling apart.
Ive had a few 400s, although roughly the same engine, it always seemed the 400s were a little hard on their bearings.
351M/400s biggest problems were the smog years killed their power. I think if you ad a pre 1972 timing chain where the cam timig isnt retarded in th cam gear it will help alot, and its a cheap upgrade.
Ive had a few 400s, although roughly the same engine, it always seemed the 400s were a little hard on their bearings.
351M/400s biggest problems were the smog years killed their power. I think if you ad a pre 1972 timing chain where the cam timig isnt retarded in th cam gear it will help alot, and its a cheap upgrade.
Cargo Master
Joined: Dec 2004
Posts: 2,232
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From: NE Texas
Yes on some of the earlier engines, the cam was retarded, but changing cam timing is a cut and try issue. BTDT.
Unless the 400 was lugged alot, overrevved alot or the oil and filter not changed as often as it should be, the 400 is no worse on bearings than anything else.
Unless the 400 was lugged alot, overrevved alot or the oil and filter not changed as often as it should be, the 400 is no worse on bearings than anything else.
Elder User
Joined: Oct 2007
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Yes on some of the earlier engines, the cam was retarded, but changing cam timing is a cut and try issue. BTDT.
Unless the 400 was lugged alot, overrevved alot or the oil and filter not changed as often as it should be, the 400 is no worse on bearings than anything else.
Unless the 400 was lugged alot, overrevved alot or the oil and filter not changed as often as it should be, the 400 is no worse on bearings than anything else.
Still a good engine though, two of my vehicles have them.
I replaced the bearings in the Galaxie, it had just under 100K miles if I remember correctly, the pan was clean. The bearings didnt look very good.
Hotshot
Joined: Dec 2003
Posts: 18,423
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From: iowa
351Ms , Cs and 400s had a low oil pressure problem, moreso at idle.
Still a good engine though, two of my vehicles have them.
I replaced the bearings in the Galaxie, it had just under 100K miles if I remember correctly, the pan was clean. The bearings didnt look very good.
Still a good engine though, two of my vehicles have them.
I replaced the bearings in the Galaxie, it had just under 100K miles if I remember correctly, the pan was clean. The bearings didnt look very good.
Cargo Master
Joined: Dec 2004
Posts: 2,232
Likes: 3
From: NE Texas
Low oil pressure in and of itself is not an engine killer. Low oil pressure raises flags in many cases because it is indicating worn bearings.
During the oil embargo of the seventies, Cummins was looking for ways to make their engines more fuel efficient. One of the many fuel efficiency improvements that they implemented was LOWERING the oil pressure. They used a relief valve that regulated the oil pressure DOWN to a MAXIMUM of 15 PSI. This required less power to drive the pump resulting in less fuel usage. The engines lived and continue to live their normal long life with this oil pressure.
During the oil embargo of the seventies, Cummins was looking for ways to make their engines more fuel efficient. One of the many fuel efficiency improvements that they implemented was LOWERING the oil pressure. They used a relief valve that regulated the oil pressure DOWN to a MAXIMUM of 15 PSI. This required less power to drive the pump resulting in less fuel usage. The engines lived and continue to live their normal long life with this oil pressure.