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is an rpm non airgap intake gonna be enough for my 408w? its in a 67 coupe, 3.70 rear gears (may go 3.50) and an auto with a 2400 stall. 10.2 compression, afr205 heads, rpm crank, eagle h beams and lunati forged pistons. Cam has not been chosen yet, just came accross a rerally good deal on an intake.... its gonna be hydro roller.

Car is 85-90% street, full interior "take the kids for icecream" with a few passes down the 1/4 a year
 

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is an rpm non airgap intake gonna be enough for my 408w? its in a 67 coupe, 3.70 rear gears (may go 3.50) and an auto with a 2400 stall. 10.2 compression, afr205 heads, rpm crank, eagle h beams and lunati forged pistons. Cam has not been chosen yet, just came accross a rerally good deal on an intake.... its gonna be hydro roller.

Car is 85-90% street, full interior "take the kids for icecream" with a few passes down the 1/4 a year
Nope. Get the Air gap or Victor JR. That being said you will still make lots of power with the RPM but you will be leaving horsepower on the table regardless of your cam choice
 

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is an rpm non airgap intake gonna be enough for my 408w? its in a 67 coupe, 3.70 rear gears (may go 3.50) and an auto with a 2400 stall. 10.2 compression, afr205 heads, rpm crank, eagle h beams and lunati forged pistons. Cam has not been chosen yet, just came accross a rerally good deal on an intake.... its gonna be hydro roller.

Car is 85-90% street, full interior "take the kids for icecream" with a few passes down the 1/4 a year
Here is the issue with a Air Gap, it is about a 1/2 inch taller than the RPM, the RPM intake can be run with a 1/2" carb spacer and not run into clearance issues with most drop base air cleaners. With the Air Gap you will probably get it to fit under the stock hood but you can not run much if any carb spacer.

In my case the carb spacer seems to help keep the fuel from boiling of in the carb and prevent hard starting issues when you turn the car off in the summer and try to re-start it.

A air gap intake might have some of these same heat isolating benifits as well, as that is the intended design or marketing for the air gap... maybe someone else can confirm?

I doubt you could feel or notice the extra HP that a Air Gap would make over a RPM intake on a 408w...any bigger like a Vic Jr will not fit under the stock hood.
 

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Ran the RPM on a 408W we built with AFR heads since the customer only wanted 500HP and it was pulling vacuum at higher RPM. This was a mild cam , mid 220 duration and only 9.7:1 compression so with your compression and bigger heads you have the potential to make more power. Run the Victor JR or Air gap, they ate the same height
 

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Hellos dads67Coupe . I also struggled with the same issue when getting my Smeding performance 427 Stroker for my 66 fastback. I did not want to cut my hood open for a scoop. The car was already painted. Smeding Performance advertised their 427 cobra stroker motor at 560 torque and 560 HP with a Victor jr intake. So I was concerned but the builder said it would not be n issue to run the RPM Performer intake.. Well my 427 stroker with the RPM performance intake came in at 576 HP at 5800 RPM and 569 Lbs torque at 4500 RPM flywheel numbers on and engine dyno.

The RPM performer is rated at 1500 t0 6500 RPM Air Gap rated at 1300 to 6500 RPM Victor Jr at 3500 to 8500 RPM.
I use my car for cruisin and having fun on the Good-guys autocross and I am not at 6500 RPM very long if at all. I am very happy with my set up.

I have a T5Z 5speed for now with 370 Posi.

Good luck hope that helps.

Bob66
 

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Run the Victor JR or Air gap, they are the same height
Manifold height per Edelbrock:

RPM: A-4.30", B-5.30"
Air Gap: A-5.31", B-6.19"
Vic Jr.: A-5.75", B-5.75"

Because the vic jr. is level, it will cause the front of the air cleaner to be higher in a car as compared to an air gap.
 

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Here's a test where they compare the Victor Jr and Air-Gap:
At the conclusion they mill the standard Performer's plenum opening in a similar fashion to the Air-Gaps and it works fairly well.

I have a new Edelbrock Performer Air-Gap in the box. It would look great in a Pantera. The air gap section is a lowered section below the runners and it looks like it might collect liquid. Chances are the stock air cleaner will not fit. It seems like overkill on my Cleveland engine, but I bought it because it fits most Cleveland heads. I've read how a small single-plane can work great on the street with a carb spacer. But you generally have to retune the carb to work with the spacer.
 

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Here's a test where they compare the Victor Jr and Air-Gap: Edelbrock Intake Manifold Dyno Test :: Single Vs Dual + Air-Gap Vs Regular
At the conclusion they mill the standard Performer's plenum opening in a similar fashion to the Air-Gaps and it works fairly well.

I have a new Edelbrock Performer Air-Gap in the box. It would look great in a Pantera. The air gap section is a lowered section below the runners and it looks like it might collect liquid. Chances are the stock air cleaner will not fit. It seems like overkill on my Cleveland engine, but I bought it because it fits most Cleveland heads. I've read how a small single-plane can work great on the street with a carb spacer. But you generally have to retune the carb to work with the spacer.
thats a dag blaime video of a chebby enjine you posted on a FORD forum ! wth !
 

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Discussion Starter #9 (Edited)
anyone know for certain if an air gap or vic jr will fit under a stock hood on a 351 swap? Or another intake that will work well with the combo and clear the stock hood
 

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Interesting replies. I have always heard that the difference between an RPM (which I have) and an air gap are negligible. That said, if I was starting from scratch with that combo you're talking about, I'd go with air gap or Vic Jr.

This isn't a deciding factor but the air gap sure looks cool.

On another note, consider a TFS stage 2 cam. It's a good mix of rowdy + streetable with a little emphasis on turning RPM vs low end torque, and that combo should be pretty happy with that.
 

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Discussion Starter #11
Interesting replies. I have always heard that the difference between an RPM (which I have) and an air gap are negligible. That said, if I was starting from scratch with that combo you're talking about, I'd go with air gap or Vic Jr.

This isn't a deciding factor but the air gap sure looks cool.

On another note, consider a TFS stage 2 cam. It's a good mix of rowdy + streetable with a little emphasis on turning RPM vs low end torque, and that combo should be pretty happy with that.
For the small price difference between an off the shelf cam and a custom ground one from woody, I'll end up going custom I think
 

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Interesting replies. I have always heard that the difference between an RPM (which I have) and an air gap are negligible.
you might be thinking of the RPM versus Air Gap for the 289/302 block which i've heard are basically the same (unlike the 351w flavors)?
 

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before you select an intake, select your cam. because this engine will spend at least 80% of its time on the street, and because it will see very little track time, i suggest getting a cam that works best in the 1500-6000 rpm range. with the 408 that will give you plenty of low end torque, from the stroke, and plenty of mid range power, from the cam, and you likely will not see anything above 6500 rpm anyway, you dont need the air gap or victor jr intakes, so the rpm is likely the one you will go with.

do yourself a favor and try to avoid the "if some is good, and more is better, then too much is just right" attitude that some people have when building engines. big power numbers are great, but we dont drive dynos.
 

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Discussion Starter #16
Im not stuck on a particular number. 500 would be great, but 400-500 is plenty for whatever Im gonna do with it. Shooting for a particular number is a good way to end up with a car thats miserable to drive
 

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Im not stuck on a particular number. 500 would be great, but 400-500 is plenty for whatever Im gonna do with it. Shooting for a particular number is a good way to end up with a car thats miserable to drive
Even a mild 408W will usually make close to 500HP at the flywheel and probably just as much TQ. When you look at intakes your basic choice is the Stealth,RPM, Air Gap or Victor JR. With the Stealth and RPM giving you the most hood clearance. Ron Morris has the 1/2" drop mounts that will help when using the Air Gap. You would need a good drop base air cleaner to clear the stock hood with the Air Gap. When you look at the RPM range of the intakes keep in mind those are for a 351W not a 408W. The RPM range of the Intakes will be at a lower number with the 408. Whatever cam you use will also be tamed down by the extra cubic inches of the 408. So a cam that is a little radical for a 351 may be a little mild for a 408W
 

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I can't fathom why anyone would build a 408, and kill it with a mild "performance" intake meant for 57 less cubic inches. I use the term performance mildly. Build a 351 with good heads, and a shorter intake, if hood clearance is your concern. It'll perform better, and before anyone starts talking dyno number......yawn.
 

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Not a nickels worth of difference between the air-gap and RPM or the Victor jr. in the overall scheme of things. Not enough to "feel" anyway...(on the butt-o-meter scale)
That leaves...which one looks the coolest when I raise my hood!? Single plane Victor gets my vote for that.
Unless you abandon the...."no-hole-in-da-hood-theme". Then spring for a tunnel ram.
6sally6
PS...Keep in mind on the cam.....tight LSA(107-110*) gives killer torque at the expense of lower(er) vacuum and slight drop in fuel mileage. With 427 cubes...you AIN'T worried too much about fuel mileage. Don't be afraid of tight LSA's and plenty of duration!
You have...1. light weight
2. big cubic inches
3. good stiff gears
in your favor.
Put a nice size cam in it and worry about rear tires!
 

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That leaves...which one looks the coolest when I raise my hood!? Single plane Victor gets my vote for that.
6sally6
if you want the "what looks coolest when i open the hood" look, then pop for one of these;

Intake Manifolds

and they will allow enough airflow to satisfy the 408 with ease.
 
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