Best Intake for a 408

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V8-valiant

V8-valiant

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Hello, I’m changing up my 408 a bit and need an intake manifold. Probably 6-8 years ago the “go to” was the rpm air gap. This is a street/strip car, it’s a 408 with 10.5-1 compression, auto 3800 stall and a 3.91-4.10 gear. Looking for opinions on the best all around intake manifold before I just jump on another air gap.
 
That combo and driving style will want a single plane. There are combos like yours running Air Gap intakes and do great but with yours I would be inclined to say it is a good candidate for a Victor. It could probably do good with either but a lot of people have single planes on lesser combos that should probably use the Air Gap.
 
The best dual purpose all around intake is the RPM.
Depending on the camshaft and the head flow specs, or AKA, a well ported head over a stock or mildly modified head, the single plane intake would be the better choice for the top end and probably not a loss down low ether. There could be a 40+ hp gain.

But again, how well the heads are ported and the cam being used has a ton of say in that.
 
Where in the powerband you looking to gain ?
more likely there gonna be loss/gain compromise with swap.
Can't see one of the other dual planes being better so were talking single plain which comes with a probable loss to mild to low with possible gain up high unfortunately only one way to know is try.
 
273 said:
Where in the powerband you looking to gain ?
more likely there gonna be loss/gain compromise with swap.
Can't see one of the other dual planes being better so were talking single plain which comes with a probable loss to mild to low with possible gain up high unfortunately only one way to know is try.
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With a 3800 stall and 3.90-4.10 gears, what kind of cam do you think will work with this type of combo?

Think about it.
 
rumblefish360 said:
With a 3800 stall and 3.90-4.10 gears, what kind of cam do you think will work with this type of combo?

Think about it.
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Doesn't say anything about the heads and depending what's more important street or strip,
But in around 240 @ fifty, 105-108 lsa lift depending on heads.
 
@V8-valiant What year is that ride and what does it weigh in at?
Heads ported? What cam is in it now and will there be a sizable change?
Hyd., solid, roller or not?
 
273 said:
Doesn't say anything about the heads and depending what's more important street or strip,
But in around 240 @ fifty, 105-108 lsa lift depending on heads.
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True. A bunch depends on his answers to my questions.
A 408 is large enough, depending on parts used of course, to use a single plane without low end loss against the RPM.
 
rumblefish360 said:
True. A bunch depends on his answers to my questions.
A 408 is large enough, depending on parts used of course, to use a single plane without low end loss against the RPM.
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True, was just trying to point out to the OP when your trying to fine tune your build good to know where in your powerband your looking for the gains and those gains can possibility sacrifice other parts of the powerband.
 
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shifting@6500 single plane
shifting@ 5500 air gap
et more important single plane
low end torque under 4000 air gap
i agree try the victor keep what works sell the rest
cam heads will tell the story
 
Let's see, 10.5-1, 3.91 gears and a fair amount of stall. Unless it weighs 4000 pounds or is going in a dump truck, single plane, every time. A 4" engine (unless you do something stupid) will have plenty of bottom end with a single plane.
 
Missing head and cam info. But, assuming it’s a mild Eddie type deal with a semi typical 240 ish@ 50 solid camshaft…I would run the airgap, and not think twice.
better all around manifold for something with the above parameters, and the dinky vert screams airgap too.
I ran the airgap on a 360 with lots more cam and vert, and a bit less compression, and the airgap was a great fit, car ran impressively for what it was.
I doubt a Victor would run better on the street or strip in such a combo
 
33IMP said:
Still is. (for a street/strip car).
Edit: i would try the rpm and the victor, see which one i liked, and sell the other.
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^^^ This. Until you try both with the rest of your combination, you won't know for sure. If you don't want to spend the money to test 2 intakes, I'd lean towards a Victor 340. As others have mentioned, you have enough cubes to overcome any low end torque issues that a single plane might cause.
 
273 said:
those gains can possibility sacrifice other parts of the powerband.
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I think I know where you’re going. Would you care to expand on that a tad?
justinp61 said:
Let's see, 10.5-1, 3.91 gears and a fair amount of stall. Unless it weighs 4000 pounds or is going in a dump truck, single plane, every time. A 4" engine (unless you do something stupid) will have plenty of bottom end with a single plane.
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I agree. In this case with the OP, his Avatar car is a small A body.
How heavy can it weigh?
B3422w5 said:
Missing head and cam info. But, assuming it’s a mild Eddie type deal with a semi typical 240 ish@ 50 solid camshaft…I would run the airgap, and not think twice.
better all around manifold for something with the above parameters, and the dinky vert screams airgap too.
I ran the airgap on a 360 with lots more cam and vert, and a bit less compression, and the airgap was a great fit, car ran impressively for what it was.
I doubt a Victor would run better on the street or strip in such a combo
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I agree. Even more so if the car is heavy-ish. I don’t see a 3800 converter as dinky. Street wise, it’s about what I’d expect. Normally you hear something like a 3500. This looks like a S/Strip deal so far. But time will tell when the OP comes back.

A 240@050 solid is still very streetable. Stroker or not.
 
rumblefish360 said:
I think I know where you’re going. Would you care to expand on that a tad?
Click to expand...
I could be wrong but seems to me OP goals are vague, is he looking for improvement on the track ? Does it need more top mid or bottom ? What parts of the powerband you spend most of the quarter mile time on and possibly focus on most to least etc..

Add I guess that miss answered your questions, just generally especially at higher hp per cid most additional mods to a fairly well built engine are only gonna improve part of the powerband and can subtract from others but not always.
 
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The best.....
IMG_20200613_194340.jpg

Bow to the tunnel ram...
 
Best? For what kind of driving and RPM?

every intake mentioned is good at something.

we need to know about your specific combo and the driving you want to do.
 
Have your vert reworked for higher stall. Go with single plane.
 
I miss read thought the OP already had the air gap
Carry on :)
 
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