Engine Dilemma
Junior User
Joined: Jan 2012
Posts: 51
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From: Farmington, MO
My opinion, since you currently have a truck and two engines already paid for; finish going through the rest of the truck to make it roadworthy AND safe then decide if you want to do the engine rebuild/swap. You could put the 351M into wet storage until you get to the point where you can rebuild it if you want to. I'm sure someone on here has a plan for how to best accomplish this. I know there are those who would rather walk than drive a 351M but mine has one and I am very satisfied with it. It also depends on what you intend to do with your truck.
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Joined: Apr 2004
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With some very limited exceptions like SCJ 428s, there is no "numbers matching" in Fords. There is an engine code in the VIN, but that's it.
Now you may think an all-original '70s-'80s PU would become some highly valuable collectors item if you were to keep your 137 horse 351m in there, but you would be fooling yourself. If anything, the 351m makes it worth LESS, as they were a dog new, and they are a dog now, and there is really no fixing that given the pistons available for that engine.
These trucks were built in massive numbers. There is nothing really special about them, other than that they are good trucks. Just like millions of other good trucks available.
As far as the 351m vs. 400, note my comment to get some decent pistons in the 400.
Don't fool yourself and pour money into one of these to keep it "original" under the false premise that it will then be worth a lot more. It won't.
ymmv, good luck with it whichever way you decide.
Now you may think an all-original '70s-'80s PU would become some highly valuable collectors item if you were to keep your 137 horse 351m in there, but you would be fooling yourself. If anything, the 351m makes it worth LESS, as they were a dog new, and they are a dog now, and there is really no fixing that given the pistons available for that engine.
These trucks were built in massive numbers. There is nothing really special about them, other than that they are good trucks. Just like millions of other good trucks available.
As far as the 351m vs. 400, note my comment to get some decent pistons in the 400.
Don't fool yourself and pour money into one of these to keep it "original" under the false premise that it will then be worth a lot more. It won't.
ymmv, good luck with it whichever way you decide.
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More Turbo
Joined: Mar 2012
Posts: 724
Likes: 26
From: Southeast Salt Lake, UT
Thanks guys, this is some awesome input. I might be anxiously getting ahead of myself as I don't really know how well the 400 runs. However, this gives me a more well rounded perspective to work with.
As of now, if everything else goes well, I'm more inclined to put the 351M back in but not in a rush. I'm now saying this because it's a spare engine and not because it's the original.
Here's my best case scenario:
I get the truck running acceptably. Start tearing the 351 down slowly and hang out on the 335 forum for guidance and inspiration. I slowly start putting it back together as money and time allows. Maybe I should look at getting a replacement gear box and t/c too, isn't there a 5-speed you can bolt to this guy?
If the 400 is crap I guess I'll reassess from there.
As of now, if everything else goes well, I'm more inclined to put the 351M back in but not in a rush. I'm now saying this because it's a spare engine and not because it's the original.
Here's my best case scenario:
I get the truck running acceptably. Start tearing the 351 down slowly and hang out on the 335 forum for guidance and inspiration. I slowly start putting it back together as money and time allows. Maybe I should look at getting a replacement gear box and t/c too, isn't there a 5-speed you can bolt to this guy?
If the 400 is crap I guess I'll reassess from there.
Super Moderator
Joined: Apr 2004
Posts: 34,513
Likes: 2,824
IF the 400 is crap, check the bore. If it is original, and the crank is good, you have the basis for a decent engine. You can run the 351m while rebuilding (with proper pistons and cam) the 400. You really don't need to do much else to the 400 and you will see a substantial power increase with no mpg penalty. Of course, you can do more, but that's up to you.
As for a 5er, the ZF 5 speed from a 460 will bolt up, but there are issues with the pilot bearing. Wyoming4x4 has the rundown on that:
https://www.ford-trucks.com/forums/1...zf-tranny.html
He also has a 400 and you can read all about it here:
https://www.ford-trucks.com/forums/1...0-ford-4v.html
As for a 5er, the ZF 5 speed from a 460 will bolt up, but there are issues with the pilot bearing. Wyoming4x4 has the rundown on that:
https://www.ford-trucks.com/forums/1...zf-tranny.html
He also has a 400 and you can read all about it here:
https://www.ford-trucks.com/forums/1...0-ford-4v.html
Thread Starter
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More Turbo
Joined: Mar 2012
Posts: 724
Likes: 26
From: Southeast Salt Lake, UT
IF the 400 is crap, check the bore. If it is original, and the crank is good, you have the basis for a decent engine. You can run the 351m while rebuilding (with proper pistons and cam) the 400. You really don't need to do much else to the 400 and you will see a substantial power increase with no mpg penalty. Of course, you can do more, but that's up to you.
As for a 5er, the ZF 5 speed from a 460 will bolt up, but there are issues with the pilot bearing. Wyoming4x4 has the rundown on that:
https://www.ford-trucks.com/forums/1...zf-tranny.html
He also has a 400 and you can read all about it here:
https://www.ford-trucks.com/forums/1...0-ford-4v.html
As for a 5er, the ZF 5 speed from a 460 will bolt up, but there are issues with the pilot bearing. Wyoming4x4 has the rundown on that:
https://www.ford-trucks.com/forums/1...zf-tranny.html
He also has a 400 and you can read all about it here:
https://www.ford-trucks.com/forums/1...0-ford-4v.html
Can't I do this to the 351 as well? From what I've been able to gather the 351M is basically a 400 with a different crank. I don't think I'll have the time, money or patience to do 2 builds.
Super Moderator
Joined: Apr 2004
Posts: 34,513
Likes: 2,824
The problem with the 351m is there are no easily obtained pistons that will give you the 9.3 CR you can get in a 400. Thus, for performance, you go 400. The piston sits down the hole in the 351m, a real performance and economy killer.
If you must, for budget reasons, stick with the 351m, a cam change, along with the "straight up" cam timing, will be an improvement. How much, I do not know. There is one other fellow massaging his 351m on the boards--headers, 4bbl, straight up timing. Not sure if he's done a cam. If I find that thread, I'll post a link.
If you must, for budget reasons, stick with the 351m, a cam change, along with the "straight up" cam timing, will be an improvement. How much, I do not know. There is one other fellow massaging his 351m on the boards--headers, 4bbl, straight up timing. Not sure if he's done a cam. If I find that thread, I'll post a link.
Senior User
Joined: Mar 2008
Posts: 273
Likes: 1
The 400 has more torque than the 351M. Torque is what you want in a pickup.
Installing the cam with straight up timing instead of the stock 4 degree retardation will help more than anything to bring whichever engine to life.
Robert
Installing the cam with straight up timing instead of the stock 4 degree retardation will help more than anything to bring whichever engine to life.
Robert
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More Turbo
Joined: Mar 2012
Posts: 724
Likes: 26
From: Southeast Salt Lake, UT
What is this going to do to my emissions? I'm in an emission testing county. All of this sounds pretty good but I need it to pass emissions. My priorities are reliability and economy. I know, then why did I buy a 33 yr old Ford? Gotta live one way or another.
As much as I'd love to do all kinds of super cool souping up of the engine I don't know if I could afford it, parts, time, gas or emissions wise.
If the 400 is a better engine on this block and from what I saw on the 335 sticky post, couldn't I just change out the crank, pistons and anti vibe and make the 351 a 400?
As much as I'd love to do all kinds of super cool souping up of the engine I don't know if I could afford it, parts, time, gas or emissions wise.
If the 400 is a better engine on this block and from what I saw on the 335 sticky post, couldn't I just change out the crank, pistons and anti vibe and make the 351 a 400?
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Super Moderator
Joined: Apr 2004
Posts: 34,513
Likes: 2,824
Crank and pistons makes a 351m a 400.
Last time you smogged, did they give you a print out?
What do they test, pipe only, or visual?
The print out may tell what they test, the limits and what your vehicle did on the test. This will tell you how much room you have on stuff like Nox and HC.
Do you still have cats on the vehicle?
Last time you smogged, did they give you a print out?
What do they test, pipe only, or visual?
The print out may tell what they test, the limits and what your vehicle did on the test. This will tell you how much room you have on stuff like Nox and HC.
Do you still have cats on the vehicle?
Thread Starter
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More Turbo
Joined: Mar 2012
Posts: 724
Likes: 26
From: Southeast Salt Lake, UT
Crank and pistons makes a 351m a 400.
Last time you smogged, did they give you a print out?
What do they test, pipe only, or visual?
The print out may tell what they test, the limits and what your vehicle did on the test. This will tell you how much room you have on stuff like Nox and HC.
Do you still have cats on the vehicle?
Last time you smogged, did they give you a print out?
What do they test, pipe only, or visual?
The print out may tell what they test, the limits and what your vehicle did on the test. This will tell you how much room you have on stuff like Nox and HC.
Do you still have cats on the vehicle?
I really haven't rolled around underneath it much yet and haven't noticed if it still has cats.
If the only thing I have to do is put a crank and pistons in. I'll do that if/when the 351 gets rebuilt. Maybe I'll put the non retarded cam in. If there are any more tricks to be done it will have to be on the top end and have to wait.
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