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chevy_power427 10-20-2007 07:13 PM

Intake Manifolds Dual plane Vs Single Plane
Hi guys, I was wondering if there are some of you out there running Single plane intake manifolds in the street and how to they perform. Are they worth the jump from a dual plane, or are they just asking for trouble. I currently have a 355 Chevy with 10.75cr vortec heads and a big Lunati cam 300deg 0.515lift with a hi rise dual plane.

curtis73 10-20-2007 07:32 PM

With that engine, I would suggest an RPM air gap. Car Craft and Hot Rod both have done tests comparing low duals, high singles, and high duals like the air gap and have shown that the RPM air gap really is the best of both worlds... only drops a couple hp on top and still maintains the torque down low.

If you had a 383 that can use the extra air, or more heads that would take advantage of the top end breathing, or a race-only setup, I'd suggest maybe a single, but it takes a lot of engine to need more than an RPM air gap.

chevy_power427 10-20-2007 08:06 PM

That's exactly with I got, well not really, but an imitation rpm air gap. I found it did well, but I just want to squeeze out some more hp for the strip.... while still driving in the streets

curtis73 10-20-2007 08:36 PM

I personally think you'd only get a couple unnoticeable hp at the strip and have to deal with cruddy street manners, especially when cold. You might actually net an overall loss of performance with a single if you end up giving up a significant torque number with a single.

usually single planes really shine on the street in engines that don't worry about torque and they have so many cubes to support that the single is really needed. I'd put a single on a 572 in a heartbeat. So what if your torque drops from 650 down to 620, you can't use it all anyway. :mwink:

chevy_power427 10-22-2007 03:23 PM

That's exactly what I thought, but I read this article that put me seriously in doubt.

They tried both on the same engine, and didn't lose that must torque.
Anyone has a second opinion?

firestone 10-22-2007 03:38 PM

One thing to keep in mind about the article is that it only stands for full throttle. Most of the time, on the street, you are at partial throttle even when you are getting on it. I beleive that this will suffer with the single plane. I think is fun to have a snappy half throttle motor. Also, I cannot refute what the article says about the low end torque, but I have seen articles that suggest different. I think it just depends on the combination.


glen242 10-22-2007 07:21 PM

Some Things I Wonder:

Why do people with a 355 have a user name of chevy_power427??

Since I don't have a 427 but only a 383 SB, I tend to ignore posts concerning big blocks. Yes I know you can get an aftermarket SB in 427, but if the poster does not have one, why include it in your signature?

Rick WI 10-22-2007 07:46 PM

You would likely pick up power above 5000 RPM with a Super Vic style intake. With that cam and wanting to run at the strip it would not be a bad upgrade for those conditions. It will run just fine on the street with that intake, we run them all the time.

chevy_power427 10-22-2007 08:19 PM

Thanks, I knew there were people out there with those intakes in the streets.

By the way, I picked out my user name way before I built my motor, it's just because I like to daydream about one in a vette.... :rolleyes:

baddbob 10-22-2007 08:34 PM

I've run three single plane intakes on 350 and 400 Ci engines on the street with plenty of part throttle power but the RPM airgap is definately a good intake. A Weiand Team G, Victor Jr, or similar would probably shine on your combination considering the 300 duration cam and if the rest of the driveline is matched to higher RPM use. Your idle will also smooth out just a tad.

chevy_power427 10-22-2007 09:01 PM

What about vaccuum at idle? Would it drop?

HammerGVette 10-22-2007 09:19 PM

I have a Edlebrock Torker II on my 350, and I will say; the bottom end is a little saugy, but you can't beat the top end performance. After about 1800 rpm, the single plane really takes into its element. I have the stock heads on the engine at the moment,though. I'm pretty sure with better flowing heads, it just about take care of the issue. It all kinda depends how you drive your car too. Me myself, drive my car like I stole it at every light (gas prices and all). So not having much power at 1000-1500 rpm, doesn't really bother me. Now if your trying to putt around town and keep the car under 2000 rpm, a dual plane is definetly what I would suggest. But what fun is that. That what 4 bangers are for... not your chevy V8 :evil:

65 Imp SS 10-22-2007 09:21 PM

I also wondered about the difference. This is from a previous post I had and my own dyno comparison.

"So where was the best power made-Dart or Airgap? I've got a Team G and also an airgap for my 468 and can't decide which I should run..."

I'm not sure of your combination and after having my dyno run (firm believer) it helped in ending speculation. This is what I had posted previously and got the idea for comparison.
"I agree with hotrodf1, I have an old article from Hot Rod november 1990 called "The Lash Word" (yes it's a bbc write up). The 454 engine used was a "Sat. night special" and compared cams (hyd,solid,roller) and also oval port intakes (weiand 8013,torker II,Holley strip dom, Dart). Now the hyd cam was healthy (comp cams 292H) that even at low rpm Dart hp& torq equaled if not bettered the the dual planes.
So when I saw that I decided (with my sat. nite special bbc 427)on my dyno run I was going to compare my edelbrock rpm with a Dart intake (oval port). The Dyno guy figured the rpm would be the only way to go. But after the dyno pulls we were both surprised and he said the Dart was the way to go. With the rpm intake the right and left A/F ratio was off.. Yes staggering the jetting might of worked but the dart was right on. Now every application is different, but after the dyno run it made me a little more open minded."
Now the tq started earlier on the air gap but the peak hp occured about the same rpm as the dart. Air gap 525hp@6400 500#tq@4300rpm. Dart 540hp@6300rpm and 500#tq@4600rpm and again the a/f ratio was off on the air gap. I'm not saying one is better than the other but in my application the dart worked and your results might be different.

chevy_power427 10-22-2007 09:28 PM

Another thing, my car has a 3.73 gear in the rear, my car rarely runs at 1250rpms i'm always driving at a higher speed, it's not a daily driver, I think I don't even drive it one a week. I could also combine it with a four hole carb space to improve signal to carb. As said earlier, I have a long duration camshaft which is made to match that intake.

SS66chevelle 10-23-2007 01:23 PM

1 Attachment(s)
I have a single plane victor jr. on my 355 powered '65 chevelle conv't (not to be confused with my 66 zz502 hard top, hence the name GLEN :) anyway, it came on the car when I bought it and it sux.. No power until ~3000 RPM and with a stock low gear and auto trans = snotty rice burner coffee can muffler kid gets you off the line every time. I just ordered a dual plane idle-5800 rated intake. The car is just a cruiser, not a racer but that doesn't mean I can live with seeing the back end of a clapped out 1990 honda either... If you are driving on the street stick with the dual plane.. .

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