400
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Junior User
Joined: Jun 2006
Posts: 63
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From: Evanston, WY
400m
Hey does anyone know for sure if the 1978 Ford F250 400 engine is a small bloxk or a big block. I have read that it is the same as the 351M with a taller deck height. Does anyone know foe sure?
Elder User
Joined: Feb 2006
Posts: 694
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From: New Gretna, New Jersey
It's the same block as the 351M, just with a different stroke I think. I'm not exactly sure on all the specifics, but there are other people on here who are more knowledgeable then me. Check the engine forums. There is a ton of this kind of info in there.
Elder User
Joined: Feb 2006
Posts: 694
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From: New Gretna, New Jersey
I don't think its technically a big block(429,460,..). It also isn't a small block(289, 302, ...). Its somewhere in between. Like I said, the engine forums have stuff like this all over them. You should check them out.
BTW, Welcome to FTE!
BTW, Welcome to FTE!
Thread Starter
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Junior User
Joined: Jun 2006
Posts: 63
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From: Evanston, WY
400m
I was wondering if anyone knew for sure if the 400m in my 1978 f250 is a big block or a small block. I have read that it is a small block with a taller deck height. But the valve covers look like they are big block valve covers. Also if it is a small block, would i be able to put 351c heads on it? Any info would be greatly appreciated. Thanks.
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Joined: Dec 2002
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From: chicago burbs
it's not a 400M, it's a 400. it's not a big block, or a small block, small and big block are chevy terms. what it is is it's a 335 series engine. 351C 2V heads are a direct interchange fit on a 400, they are both 335 series engines. 351C 2V heads do not have any emission features that the 78 heads have, but they do have better exhaust ports.
Last edited by grclark351; Jun 11, 2006 at 03:28 PM.
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Junior User
Joined: Jun 2006
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From: Evanston, WY
Thanks alot. Would you recomend the 351c heads on my 400 or should i go with a different setup?
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Posting Guru
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From: chicago burbs
depends upon if you need the emission features for visual inspection or not. the C heads are better than stock 78 heads.
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Postmaster
Joined: Apr 2002
Posts: 3,613
Likes: 6
From: Coal country
You have posed an excellent question.
There is no Ford "big block" or "small block" designation. That terminology is originally GM in nature.
It has become generic in nature to mean engines over 400 CID, but when referring to Ford engines, it confuses more than anything.
Ford uses the term "Family" to differentiate between engine designs. The engine forums here on FTE are separated accordingly, and you can learn a lot just by surfing. You will notice how the FE and 385 Families span the 400 CID threshold, rendering the Big Block designation rather confusing:
Here are the basic families, as used since WWII:
Y-Block: 292 and 312 are the most common, used up to '64 in trucks.
FE, Ford Edsel engines: 332, 352, 360, 390, 406, 410, 427, 428. First used in light trucks in '65, discontinued in '76.
FT, Ford Truck: 361, 391, a heavy duty variant of the FE
Windsor series: 221, 260, 289, 302 (5.0) and 351W. First used in cars in the early '60s, introduced into trucks in the late '60s. Discontinued in '95.
335 Series: This includes the 351 Cleveland, 351 Modified and the 400. discontinued in the early '80s.
385 Series: 370, 429 and 460. Used up to '95.
Hope this helps!
There is no Ford "big block" or "small block" designation. That terminology is originally GM in nature.
It has become generic in nature to mean engines over 400 CID, but when referring to Ford engines, it confuses more than anything.
Ford uses the term "Family" to differentiate between engine designs. The engine forums here on FTE are separated accordingly, and you can learn a lot just by surfing. You will notice how the FE and 385 Families span the 400 CID threshold, rendering the Big Block designation rather confusing:
Here are the basic families, as used since WWII:
Y-Block: 292 and 312 are the most common, used up to '64 in trucks.
FE, Ford Edsel engines: 332, 352, 360, 390, 406, 410, 427, 428. First used in light trucks in '65, discontinued in '76.
FT, Ford Truck: 361, 391, a heavy duty variant of the FE
Windsor series: 221, 260, 289, 302 (5.0) and 351W. First used in cars in the early '60s, introduced into trucks in the late '60s. Discontinued in '95.
335 Series: This includes the 351 Cleveland, 351 Modified and the 400. discontinued in the early '80s.
385 Series: 370, 429 and 460. Used up to '95.
Hope this helps!
Elder User
Joined: May 2002
Posts: 526
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From: Sin City, USA
Originally Posted by 78FordF2504X4
I live in WY where there are no emmisions. Also do you think that i could get 500+ hp out of my 400 if i did everything right?
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Junior User
Joined: Jun 2006
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From: Evanston, WY
Yes i know this. I hope to use this truck as an advertisement for my business. I also would like it to be a hot rodder and maybe give this year and model the respect it deserves.
Elder User
Joined: Feb 2006
Posts: 694
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From: New Gretna, New Jersey
Originally Posted by Jmudder79
I'm not exactly sure on all the specifics, but there are other people on here who are more knowledgeable then me.
You picked a good site to join.
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
You do not want to build a motor for 500 HP in a truck. You should build it for high low end torque and a broad flat torque curve.
To get 500 HP you need a cam with a lot of duration. This will kill the torque at low RPM. A light Mustang can get away with this, but a heavy vehicle needs that torque.
The best combos use 9:1, or 9.5:1 compression ratio, with moderate duration high lift hydraulic roller cams, ported or alloy heads for great head flow, headers, a good intake manifold with a 600 CFM carb.
There are many examples of what others have built or are building on this forum. Our sponsor Tim Meyer has some great parts to build this motor.
To get 500 HP you need a cam with a lot of duration. This will kill the torque at low RPM. A light Mustang can get away with this, but a heavy vehicle needs that torque.
The best combos use 9:1, or 9.5:1 compression ratio, with moderate duration high lift hydraulic roller cams, ported or alloy heads for great head flow, headers, a good intake manifold with a 600 CFM carb.
There are many examples of what others have built or are building on this forum. Our sponsor Tim Meyer has some great parts to build this motor.