383 vs 400

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A lot of the DC tricks and tips are really not worth the time and effort.

We run engine that go 5.40 in the 1/8th mile and have never increased the size of the pickup, ran a high volume oil pump, or a high pressure oil pump.

Now cleaning up the oil passages we do that, but mainly just to make sure there is no obstruction and that the factory drilled them all the way.

In a normally aspirated engine the one with the larger bore has more ability to get more air because it allows for larger intake valves.

Tom
 
273 said:
echnically the 400 bore has more potential
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No matter what the 400 is only capable of 17 more cubes than a 383 with all being the same.
Even at 2hp per cube you're only talking 34 more hp. In reality much less with the average hp per cube build at 1.25- 1.5 hp per cube with a moderate build.
 
273 said:
Technically the 400 bore has more potential, question is, are you building anything that really needs that potential, lot's are making 500+ hp with around a 4" bore.

It's what you want to build has more to do with it then is it capable cause most of these engines even the lowly 318 is capable of quite a bit.
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That is all absolutely true. And I have a running 383 (with a 440 crank). And a 400 block just sitting around. You can make hp with either one. But the argument is made by some, Oh, don't build a 400, they suck! When it's the same basic engine as a 383, except with a larger bore. Other than pistons, every part of either motor is completely interchangeable. And the 400 does have 17 more cubes. No reason not to use it if you have one. And how a stock 400 smog motor performs against a stock high compression 383 is pretty much irrelevant - if you're building a performance motor you're gonna replace the pistons anyway.

And by the way, the last 383's were low compression, too. And parts store replacement 383 pistons are all low compression pistons, no matter whether you're ordering pistons for a 383 hp or a 383 two barrel or what year block you're buying them for.
 
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fishmens67 said:
No matter what the 400 is only capable of 17 more cubes than a 383 with all being the same.
Even at 2hp per cube you're only talking 34 more hp. In reality much less with the average hp per cube build at 1.25- 1.5 hp per cube with a moderate build.
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Jeez, no one disagrees with this.
 
65 Cuda 340 said:
The 400 has seventeen more cubic inches than a 383. And a larger bore with less valve shrouding. With the same CR, cam, heads, intake and exhaust, the 400 will make more horsepower. I think the 400 block is also stronger.

400s are like 360s. They got a bad rap because stock they were all low compression smog motors. Build them the same as the smaller motors and the 400 is stronger than a 383, and a 360 is stronger than a 340. And a 440 is stronger than a 426 which is stronger than a 413. Again, this is assuming everything except the cubic inches is the same.
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Robert Landy built one for Mopar Muscle in the 80s. The article was called "Triple Threat". 400HP 400TQ and 400 CI. He used some custom forged pistons and got zero or close deck height, the Crane "Magic cam" .467/.494 222/234 A.050 on a 114 and unported iron heads. I actually still have that very issue. He said they could've gotten a LOT more, but they just wanted to show how easy 400HP was.
 
fishmens67 said:
No matter what the 400 is only capable of 17 more cubes than a 383 with all being the same.
Even at 2hp per cube you're only talking 34 more hp.
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So you agree more potential.
fishmens67 said:
In reality much less with the average hp per cube build at 1.25- 1.5 hp per cube with a moderate build.
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Why I said technically has more (biggest bore) and went on saying all these engines even a 318 (2nd smallest bore) has the potential to build what most want. Never said the 400 was miles ahead.
 
273 said:
Why I said technically has more (biggest bore) and went on saying all these engines even a 318 (2nd smallest bore) has the potential to build what most want. Never said the 400 was miles ahead.
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Either way you look at it with all being the same there just isn't much bore difference to make a bunch more horsepower with the same stroke and less than 20 cube difference, probably not enough to notice it
 
fishmens67 said:
No matter what the 400 is only capable of 17 more cubes than a 383 with all being the same.
Even at 2hp per cube you're only talking 34 more hp. In reality much less with the average hp per cube build at 1.25- 1.5 hp per cube with a moderate build.
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If You're building in the 1.5hp./c.i. range, You'll take that extra 25+ hp EVERY day ALL day,....& 2× on SUNday.....what is WRONG with somebody who wouldn't???
I love My 383's, I have (5) of 'em which includes the one out of My old Dippy Cop-Car project....but I have a 400 sitting there for the next B-engine project if it materializes.
 
Killer6 said:
If You're building in the 1.5hp./c.i. range, You'll take that extra 25+ hp EVERY day ALL day,....& 2× on SUNday.....what is WRONG with somebody who wouldn't???
I love My 383's, I have (5) of 'em which includes the one out of My old Dippy Cop-Car project....but I have a 400 sitting there for the next B-engine project if it materializes.
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Not like you automatically gain power cause you built a larger engine.
 
THere are some who think the 400 will never make power no matter what since it never had compression to amount to anything. I'd love to see what a stock stroke 400 could do with some Trick Flows, a solid roller and all the other matchin stuff.
 
Killer6 said:
When it's the same stroke & piston speed, yes, yes you do...
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Debatable, I have yet to see anyone prove that especially that the larger engine will make the same hp per cid or greater than the smaller one.

So a 273 commando makes .86 hp per cid so if we built a 340 with commando parts we automatically get 293 hp ? if we upgrade to a race block with 4.20" bore we get 315 hp ? The commando cam, heads, carb, manifolds etc.. can just keep processing more and more fuel and air as we just keep on opening bore, what if we add 4" stroke to it for a 443 = 381 hp from 273 parts ?
 

RustyRatRod said:
THere are some who think the 400 will never make power no matter what since it never had compression to amount to anything. I'd love to see what a stock stroke 400 could do with some Trick Flows, a solid roller and all the other matchin stuff.
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Some peoples perception of an engine is based on if the factory built a performance version or not.

There's a 1000 hp B1 400 with stock stroke vid out there but couldn't find it.
 
273 said:
Debatable, NO, NO IT'S NOT.....

So a 273 commando makes .86 hp per cid so if we built a 340 with commando parts we automatically get 29n3 hp ? if we upgrade to a race block with 4.20" bore we get 315 hp ? The commando cam, heads, carb, manifolds etc.. can just keep processing more and more fuel and air as we just keep on opening bore, what if we add 4" stroke to it for a 443 = 381 hp from 273 parts ?..........LET'S USE YOUR OWN CARBURETOR LOGIC....."THE HEADS FLOW WHATEVER THE ENGINE WANTS!!"
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You must've got the mice in Your head on crack now, ......
 
Killer6 said:
You must've got the mice in Your head on crack now, ......
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