Intake confusion...is the AirGap too big for a 318?

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megavites

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After alot of searching, I'm still confused as to why some say the Eddy Performer RPM Airgap intake, with its bigger ports, runs well on their 318,
while many say, run the smaller port Performer intake, which is a basic 4bbl intake.
My setup is: stock 318, stockcam, stock ignition, Eddy SP2P intake.
Whiplash cam going in along with headers.
 
Dump the current intake for the performer.

The RPM is also fine for use. But the cam should match the RPM's rpm power range. The Performer and OE iron or equal from power stand points.

OPS! Which Whiplash cam?
 
318 WHIPLASH CAM 109º LSA+5

WHIPLASH SERIES FLAT TAPPET HYDRAULIC CAMSHAFT
for low compression 318, from Idle to around 5500rpm.
I was thinking of going with the Airgap...if the Performer was not much more than a warmed over 4bbl "stock" manifold.
 
factory stock cast 4bbl performs..... and I know people that spin them over 7 grand
 
yellow rose said:
Yup. Look at Stock eliminator. Those guys go very fast at 7k plus on a factory intake. And carb.
Click to expand...
I know a guy that went 11.30's with a cast intake/TQ 360 in a full size pickup, long bed, all steel....
 
Wow Rumble!

I’m on here asking…because I don’t know… and looking to the advice of others that have been down this road. From what I’ve “read”, “others” have said the eddy Performer is a basic 4bbl manifold.

The RPM and the RPM air gap are better, but typically due to 340 heads on the 318.

I’m just trying to determine if the Airgap port difference to my small port, stock 318 “675” heads would disrupt airflow too much.

Another option, is I could reinstall the SP2P for now and put a LD4B on later. Again, from what I’ve read, it’s a big step up from the “Performer”.

Cam spec
SMC1326AL.jpg
 
I'd run stock iron over that SP2P gas mileage/motorhome intake manifold.

Run any of the 4b, LD340, RPM or Air Gap. Any of them will perform well on the engine. Port window... blah... don't worry about it.

The performer 318/360 intake works better than most will give it credit for. Do a little massaging to the intake runner opening and it's right there with a RPM/AG/LD340.
 
I have a performer 318/360 on a 318 with TQ carb and it runs strong. Stock bottom end with a 220°@.050 .450 cam. Heads are home ported and manifold is port matched. I paid $75 for the intake and would not pay the extra dough for a performer RPM intake. I bet the regular performer will have better midrange anyhow.

20140115_111806.jpg
 
megavites said:
After alot of searching, I'm still confused as to why some say the Eddy Performer RPM Airgap intake, with its bigger ports, runs well on their 318,
while many say, run the smaller port Performer intake, which is a basic 4bbl intake.
My setup is: stock 318, stockcam, stock ignition, Eddy SP2P intake.
Whiplash cam going in along with headers.
Click to expand...
Something to think about...the AIRGAP manifold is better...but is it so much better that it's worth the expense? If you have money to burn, sure, buy one. If not, what you have will work just fine. If you decide to buy an AIRGAP try to think about the whole package. You may not see any real improvement without changing the cam and/or heads or without doing some significant port work. So the expense of a new manifold may be much more than just the manifold. Keep that in mind as well.
 
crackedback said:
I'd run stock iron over that SP2P gas mileage/motorhome intake manifold.

Run any of the 4b, LD340, RPM or Air Gap. Any of them will perform well on the engine. Port window... blah... don't worry about it.

The performer 318/360 intake works better than most will give it credit for. Do a little massaging to the intake runner opening and it's right there with a RPM/AG/LD340.
Click to expand...
SP2P is meant to be on a stone stock motor. I bought a truck that someone installed an SP2P with a 600 eddy carb and a cam and it is not a well thought out combo. I have a 66 273 commando intake I am thinking of replacing it with. The 318/360 intake on the 318 in my Dart runs great and only cost me $75
 
mischiefdart said:
I have a performer 318/360 on a 318 with TQ carb and it runs strong. Stock bottom end with a 220°@.050 .450 cam. Heads are home ported and manifold is port matched. I paid $75 for the intake and would not pay the extra dough for a performer RPM intake. I bet the regular performer will have better midrange anyhow.

View attachment 1715051542
Click to expand...



Don't you have to use an adapter to get the TQ on that intake manifold?
 
Megavites, sorry, I was actually feeling goofy when I wrote that.

YR, adapter for the TQ gets used on the RPM, Stealth, LD4B, M1 dual plane. Not the Performer, Action Plus, M1 single plane.
 
Damn, I tried to run a TQ on a SD many moons ago and it wouldn't open the secondaries because they hit the intake.

Some day, I'm going to do a TQ for my SD just to piss people off.
 
yellow rose said:
Damn, I tried to run a TQ on a SD many moons ago and it wouldn't open the secondaries because they hit the intake.

Some day, I'm going to do a TQ for my SD just to piss people off.
Click to expand...
You need a spacer under a TQ to keep the secondaries from hitting on a street dominator. At least on the big block ones I have.
 
get the 318/360 Perfomer used. Great lightweight intake with the right port size. If you want a little more top end, use your 66 4bbl intake with its single plane design. You can also notch your Performer LD340 style. The SP2P is a killer truck/motorhome intake, maybe fine for a smaller 273.
Vizard (induction guru) claims he can massage a stock intake to run as well as any like designed aftermarket intake, they are designed pretty good with only the lightness and thermal characteristics of aluminum making them better.
 
I run a Performer on a built 318 with 318/302 heads and I'm sure it didn't give up any power and prob better than RPM on the low range.
 
crackedback said:
I'd run stock iron over that SP2P gas mileage/motorhome intake manifold.

Run any of the 4b, LD340, RPM or Air Gap. Any of them will perform well on the engine. Port window... blah... don't worry about it.

The performer 318/360 intake works better than most will give it credit for. Do a little massaging to the intake runner opening and it's right there with a RPM/AG/LD340.
Click to expand...

^^^^^^^^^^^ Agree. I've said it before on FABO and other places--A larger intake manifold port on a smaller cylinder head port often makes more power than the reciprocal and/or a perfect port match. To answer your question the Air-Gap is going to work very very well on your 318. J.Rob
 
What's your cylinder pressure or compression ratio?

At 165psi, with a 268 or bigger cam, the AirGap is the go-to item.
At 155i, with a 268 The AirGap is starting to earn it's keep.
At 145 with a 268. The AirGap is fast becoming the wrong item
At 135 with a 268, the AirGap I would leave it in the box;this is a poor combo
At 125 and a 268, You're either ignorant, stupid, or rebellious;that is a crap street combo. Oh sorry, I didn't mean to hurt anyone's feelings,lol

Just don't put it on a smallport head, that's just wrong. The heads will tank long before the intake gets wound up.
See, the AG is sortoff a high-rpm manifold with excellent midrange capability. But the low-rpm performance will depend very heavily on the engine under it. Those big passages and the fairly large plenum want airspeed. And the teener cylinders are 12% smaller than the 360's to start with. If you put a big cam in it with a late closing intake, or if you start with an 8/1 compression, you are begging for disappointment. These combos make for slow low-rpm airspeed. And that leads to low-performance.
The AG on a strong signal, is dynomite, especially in the high rpms. But first, you gotta get there. And if the cylinder pressure is low, it's gonna take time. With 3.55s, and a 268*, it will be about 35mph before it wakes up, and 50 before it's hauling azz..And if the stock pistons are stil in there, then you are gonna need a big TC just to get rolling.
But with a 10 or 10.5 engine, and hi-flow heads,the 268* will love the AG.
It's all in the combo.
 
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