What are the main advantages/disadvantages between single and dual plane intake manifolds? It seems to me, that with a dual plane intake, you are splitting the fuel charge intake between the two banks of the engine.

 

single planes are good for engines that make a lot of power upstairs... at the cost of not being so great down low (particularly on smaller displacement motors). Not really a big deal if you've got something with plenty of torque, but on your average 350 you're going to feel it lugging pretty good until higher RPM's. Single planes will "break even" with dual planes at around 4000 RPMs, and at 6000 you start seeing some differences. You figure if you wind your motor up to 7500 RPM's - you'll probably see a big difference because the intake is not causing you any restrictions like a dual plane would typically give you.

The dual planes are better for torque and velocity across the entire powerband generally, but they are limited to a certain degree in flow characteristics. They are great for street cars, street strip, and drag racing provided they have work done to them to accomodate extra airflow that is needed to make power.

Both serve their purpose. I prefer a ported dual plane intake over a single plane, but they're both equally useful provided you use them properly as they were intended.

 

I'd like to be able to get a little more out of my motor than 5,500 rpm, but I don't know that I necessarily need to. Kinda one of those "it's nice to have it" features. The car is mainly driven on the street. Maybe taken to the strip every once in a while. I was looking at the Weiand x-celerator single plane intakes and it said that the power band is good between 1500-6500 rpm. That doesn't seem too bad to me.

 

I have a single plane victor jr on a vortec head 305 in a vette and it has all the torque it had with a dual plane and pull much harder upstairs.

 

it's not bad provided you have everything else matched properly. I've actually never had any of Weiand's intakes so I can't tell you much in that regard. EDIT: just see all the info in your profile. What's your current cam specs?

 

The intake isn't going to make it rev any higher than 5500. That's the cam.
I would not recommend putting a single plane on a motor that only revs to 5500 and is street driven. You will not be happy.

 

The cam I have in it now is the stock cam, but I'm going to be installing the manifold on a motor that I'm currently building. The cam for that motor is a comp 306. 112 LSA, 230/244 duration @.050" lift. Cam spec sheet gives a 1800-5800 rpm range.

 

No, I know that. It's gonna be determined by how the whole motor is set up. Cam, heads, intake, exhaust. I guess what I really meant was that I'm expecting this motor to make some power past 5500, and I want to make sure not to choke my motor out by choosing the wrong type of manifold. My elcamino motor ran out of motor in the top end, and I hated it. But that engine had stock heads and stock Corvette cam. I've got a set of aluminum 195cc ProComp heads with 2.020/1.600 valves for the new motor.

 

Big difference on my 350 going to an RPM air gap versus the miniram that was on there (all in the first 330'). The air gap also has no problem feeding the engine at 7000RPM. In addition, the dual plane pulled enough extra vacuum at idle and low speed that I could remove the vacuum pump and just run the power brakes the way they were meant to be run.

 

Just use a performer rpm or air gap. There's a reason everyone uses it. It's the best manifold for anything 6500 and under. And has been proven hundreds of times on dynos.

 

Will an air gap style manifold fit under our f-body hoods?

 

Word!

 

A lot of guys have reported they have been successful with a drop-based air cleaner. I have a cowl hood, so I honestly couldn't answer that. I was anticipating fitment issues, so I just jumped at a new hood and called it a day.

 

I'm also starting to think about a cowl hood...

 

RPM air gap, reproduction L88 drop base (trimmed to fi around HEI cap), a 3 " high filter, a flattened lid and a 1/2" phenolic spacer fit under my stock IROC hood...BARELY!

 

according to Edelbrock's web site the RPM and RPM Air Gap are the same height. I have an Edelbrock RPM Air Gap on my car and with the hood bumps adjusted up a little bit higher I could use my stock LG4 air cleaner. I had modified it to fit over the fuel bowls on the Holley Carb. After I got my hood repaired and set properly the stock air cleaner didn't touch with the motor off but it is so close that any twisting of the motor would cause the air cleaner to hit. My open element drop base air cleaner does not come close to my hood now.

 

well if your engine is a 305, I would go with the "performer" and not the rpm/air gap performer. The reason is the regular performer will fit under the hood with more clearance, the rpm range is more suitable to the stock cam and yet it is far better than the stock intake. The ports on the performer are small and will match up well with your stock heads. The port size on the rpm/air gap are Bigger than a vic jr! I know this from my own personal experience on my old 305. If you can wait till your new engine is built, I would go with a vic jr.