400 Rebuild
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Tuned
Joined: Apr 2002
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400 Rebuild
A friend of mine is considering rebuilding the 400 currently in his truck. Since I plan to help him out and I have never rebuilt the 351M or 400, I did some "lite" research on this engine. Please correct me if I'm wrong but it sounds like they require quite a bit of machining and custom work to get decent HP. Am I correct in my understanding that a 4bbl carb was never offered on these engines? Therefore performance cylinder heads and intake manifolds were never factory produced? Would he be further ahead to find a 460?
Posting Guru
Joined: Aug 2000
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From: (near) Denver USA
400 Rebuild
It depends on what you mean by "decent HP." To rebuild an engine for performance, the 400 requires about the same machine work (very little of it could be considered "custom work") as any other pushrod Ford V8.
You are correct that a 4V carb was never offered on these engines, and therefore, 4V intake manifolds were never produced by the Ford factory. Cylinder heads are almost identical to 351C 2V heads, and compared to most other stock heads, those are performance heads.
What is your friend's application (rock crawling, mud running, heavy trailer towing, drag racing, etc.)? That should determine how the engine is built, as well as which engine he's better off with.
You are correct that a 4V carb was never offered on these engines, and therefore, 4V intake manifolds were never produced by the Ford factory. Cylinder heads are almost identical to 351C 2V heads, and compared to most other stock heads, those are performance heads.
What is your friend's application (rock crawling, mud running, heavy trailer towing, drag racing, etc.)? That should determine how the engine is built, as well as which engine he's better off with.
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Tuned
Joined: Apr 2002
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400 Rebuild
He will do some towing (camper and skid loader)but mostly interested in something with snappy throttle response. The custom machining I refered to came from (again) things I have read about this engine series. Since these engines were not initially designed for performance, there are fewer performance parts available. Their factory designed compression ratio is low requiring "custom machine work", decking the block, planing the cylinder heads or custom work to pistons in order to achieve the higher compression ratio needed to produce horsepower. Since they were never produced with a 4bbl carb, what intake manifolds are available, after market only? Are there any factory produced 4bbl intake manifolds that fit the 351M/400M? Does a 4bbl intake off a 351C fit? Since the heads were manufactured for a 2bbl carb is it a waste of time installing a 4bbl on this engine?
Mountain Pass
Joined: Jul 2000
Posts: 189
Likes: 12
From: Minnesota
400 Rebuild
I have a interesting article on how to build a 400 that puts out 380hp and 468 lb-ft of torque for under $2000. Its a Hot Rod Sept. 98 article. Was checking some of the prices they have listed and it might actually cost a bit more in todays $. Contact me and I can fax it to you if you interested. Thinking about doing this build myself.
Posting Guru
Joined: Aug 2000
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From: (near) Denver USA
400 Rebuild
Snappy throttle response is just a matter of tuning. My wife's old '84 Escort with a 70hp wheezer had snappy throttle response.
You guys need to keep doing your research. Use the search function, or just browse a while in this forum, and you can learn a lot more about the 400.
Most performance parts made for the 351 Cleveland are either direct bolt-on, or easily adaptable to the 400.
Decking the block and heads is not considered "custom" machine work around here. I don't know of any machinist who won't deck block and heads to true them up, and knocking off a few more 0.001 inch of metal is no big deal. The most "custom" it ever gets is bushing the rods for 351C pistons, if that's the way you want to go for higher compression.
There are currently three aftermarket 4V manifolds made for the 400, including one that is emissions legal. There are several others that are no longer produced, but readily available.
If your friend wants to tow, he needs torque more than horsepower, and horsepower comes from torque and speed (rpm) anyway.
The 4V heads that you think you want are not a good design for a torque-producing truck engine.
You guys need to keep doing your research. Use the search function, or just browse a while in this forum, and you can learn a lot more about the 400.
Most performance parts made for the 351 Cleveland are either direct bolt-on, or easily adaptable to the 400.
Decking the block and heads is not considered "custom" machine work around here. I don't know of any machinist who won't deck block and heads to true them up, and knocking off a few more 0.001 inch of metal is no big deal. The most "custom" it ever gets is bushing the rods for 351C pistons, if that's the way you want to go for higher compression.
There are currently three aftermarket 4V manifolds made for the 400, including one that is emissions legal. There are several others that are no longer produced, but readily available.
If your friend wants to tow, he needs torque more than horsepower, and horsepower comes from torque and speed (rpm) anyway.
The 4V heads that you think you want are not a good design for a torque-producing truck engine.
Senior User
Joined: Jan 2003
Posts: 217
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From: Saraland AL
400 Rebuild
I built my 400 to do what your friend wants. I done the 351Cleveland piston conversion. The rest were simple bolt-ons and common modifications.
I have a Weiand 4V intake; '72 351c 2V heads with port work on the exhaust side, stainless valves, bronze guides, hardened valve seats; 268 duration, .484-.510 heavy duty cam; double roller timing chain; long tube headers; factory distributor and ignition(Duraspark).
The gear is 2.75 which hurts a little, but I'll change it sooner or later.
I have good response, good compression-9.5:1, and respectable mileage-12mpg. I'll keep tuning it and should get more out of it.
In case you're not aware, the 351c 2V, 351M, 400 heads have big ports and valves. They DON'T NEED a lot of work. In stock form, they very good street heads. Unless your friend is planning on running race fuel, you won't be able to use a lot of compression anyway.
400s were designed to do just what your friend wants. They make a good amount of torque while saving weight and fuel-as compared to an FE or 460.
I have a Weiand 4V intake; '72 351c 2V heads with port work on the exhaust side, stainless valves, bronze guides, hardened valve seats; 268 duration, .484-.510 heavy duty cam; double roller timing chain; long tube headers; factory distributor and ignition(Duraspark).
The gear is 2.75 which hurts a little, but I'll change it sooner or later.
I have good response, good compression-9.5:1, and respectable mileage-12mpg. I'll keep tuning it and should get more out of it.
In case you're not aware, the 351c 2V, 351M, 400 heads have big ports and valves. They DON'T NEED a lot of work. In stock form, they very good street heads. Unless your friend is planning on running race fuel, you won't be able to use a lot of compression anyway.
400s were designed to do just what your friend wants. They make a good amount of torque while saving weight and fuel-as compared to an FE or 460.
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Posting Legend
Joined: Sep 2001
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400 Rebuild
Build your engine as close to 1971 400 specs as possible. That was the only "good" year for the 400 before the EPA choked it to death.
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Mountain Pass
Joined: Aug 2003
Posts: 143
Likes: 2
400 Rebuild
I'm getting ready to do the same thing: have a 78 F150 with a 400 in it. Was going to go back with all stock, but have decided to see about tweaking it up a bit. Trying to keep the mpg up, yet have good power. Use the truck mostly for open road driving, but would like to tow a trailer without to much of a worry.
I have gotten a few ideas here by looking at differant post, just haven't been able to put them all together yet!
Anyhow, I did find an excellent site with a lot of information, this may help you also:
http://home.earthlink.net/~bubbaf250/index.html
Good luck and I will be watching this post, if anyone has added information for a poor shade tree mechanic.
I have gotten a few ideas here by looking at differant post, just haven't been able to put them all together yet!
Anyhow, I did find an excellent site with a lot of information, this may help you also:
http://home.earthlink.net/~bubbaf250/index.html
Good luck and I will be watching this post, if anyone has added information for a poor shade tree mechanic.
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
400 Rebuild
If you look up about three posts up from yours you will find a guy that posts here by the name of bubbaf250, that site you listed is his site 
Keep reading here, you will find more info than you need.
Keep reading here, you will find more info than you need.
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
400 Rebuild
There are only 4 things that you need in order to wake up the sleeping giant that you have.
Carburation, camshaft, compression and exhaust.
Carburation:
An Edelbrock 600CFM carb is a good choice for your stated goals. Model 1400 if you need EGR or 1406 without. Also a nice Dual Plane intake manifold like Edelbrock 3771 w/EGR 2771 without.
Camshaft: A lot of those here like Comp Cams 268 degrees. Watch emissions here if you need it. Also a dual roller timing chain is a good idea.
Compression: This is the hard part. The first choice is to find a set of Ohio/Badger/Dynagear flattop pistons. Next is to get a suitable set of 351C pistons and use bushings in the connecting rod (not recommended by a lot of people). Also use a performance head gasket.
Exhaust: a set of headers and some porting work on the exhaust port.
The heads are fine the way that they are, but you could tune them up with bronze valve guide, hardened valve seats(if necessary), stainless steel valves. You also will need springs to match your cam.
With these mods and a decent ignition you should get decent mileage and good throttle response.
Carburation, camshaft, compression and exhaust.
Carburation:
An Edelbrock 600CFM carb is a good choice for your stated goals. Model 1400 if you need EGR or 1406 without. Also a nice Dual Plane intake manifold like Edelbrock 3771 w/EGR 2771 without.
Camshaft: A lot of those here like Comp Cams 268 degrees. Watch emissions here if you need it. Also a dual roller timing chain is a good idea.
Compression: This is the hard part. The first choice is to find a set of Ohio/Badger/Dynagear flattop pistons. Next is to get a suitable set of 351C pistons and use bushings in the connecting rod (not recommended by a lot of people). Also use a performance head gasket.
Exhaust: a set of headers and some porting work on the exhaust port.
The heads are fine the way that they are, but you could tune them up with bronze valve guide, hardened valve seats(if necessary), stainless steel valves. You also will need springs to match your cam.
With these mods and a decent ignition you should get decent mileage and good throttle response.
Elder User
Joined: Sep 2001
Posts: 887
Likes: 1
From: Jax FL
400 Rebuild
Originally posted by catbird7
Please correct me if I'm wrong but it sounds like they require quite a bit of machining and custom work to get decent HP.
Please correct me if I'm wrong but it sounds like they require quite a bit of machining and custom work to get decent HP.
http://home.earthlink.net/~tcrocker/400.html
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