Intake Manifold

okokok...

I know that one component can serious affect the performance of an engine if not mated up to the rest of the compenets properly, but....

Does it really matter for intake manifolds? I don't know what the hell is on mine off the top of my head, (weiand???) but I was thinking of replacing it with an Edelbrock AirGap manifold. Do I need to take anything else into consideration, like the carb, etc??? Should Holley's only be mated up to Weiands, and Edlebrock to Edelbrock, etc???:dunno:

The Weiand version of Edelbrock's Air Gap is a single plane manifold, "intended for race applications only". So I'm not sure if that's something I should be shying away from or not if I'm not REALLY going to race it. :frown: I just want to make any rice/mopar/ford owner ashamed that he picked an inferior vehicle manufacturer to pledge his allegiance to. :smooch:

And what the hell is the difference between single plane and dual plane, etc???:banghead:

Help???

Single plane intakes provide one plenum for all 8 cylinders. Dual plane intakes provide seperate (in theory) plenums for two sets of 4 cylinders. Single planes are best suited for high-RPM use (if you plan on making power above 6,000 RPM). Dual planes are best for street cars, due to their ability to make power at lower RPMs.

Most dual planes have a plenum that feeds cylinders 1,4,6 and 7 while the other feeds 2,3,5 and 8. The basic theory is that each cylinder draws from its own plenum during its intake stroke (see the firing order), keeping vacuum across the plenum more uniform - which helps build low-end torque. For example, if we called the plenums "A" and "B", and compared them to the firing order, we'd have

1a-8b-4a-3b-6a-5b-7a-2b or a-b-a-b-a-b-a-b.

The drawback to this is that the dual plane design tends to hinder flow at the higher RPMs, while on a single plane design, the flow is consistent across the runners.

Single-plane intakes do not really make power below 3,000 RPMs, which is where you spend almost all of your time on the street.

Also, the intake is a key ingredient in the power making mix - they have airflow characteristics such as runner length, runner volume, etc. Dual planes have a complex mix too, a "high-rise" dual plane makes more power in the higher bands without sacrificing a lot down low. "Low-rise" dual planes make gobs of power down low, but fall off around 5k RPMs.

Just keep in mind that street racing requires a motor that makes torque - it's this torque that accelerates you down the road.

Weiand's version of the Edelbrock AirGap is called the Stealth Air Strike and it is a dual plane high rise intake. Their are other companies that make their own version as well. Professional Products make one called the Cross Wind intake and Dart makes one called the Koolcan intake. They all have a similar design and are pretty much the best for street use, especially with a performance cam. I have the Dart Koolcan for my Nova. Most of these intakes accept a squarebore type carb. If you want to use a spreadbore type carb like the quadrajet, you'll need to get an adapter. :grinyes:

Thanks fellas, you'd think the parts mag's would help a guy out with that stuff, but I guess they care more about the sale than whether or not you've bought the right thing.

I appreciate it, this place is great.

Oh and thanks for the Weiand Stealth Air Strike tip... It's not listed in ANY of my parts catalogs. I'm gonna upgrade from a 4150 750cfm to a 850cfm Double Pumper soon, and would like to stay with the Weiand / Holley combo.

That Weiand Stealth strike is new, that's prob why it's not listed in many books yet. Those air gap dual plane intakes are the best of both worlds (race/street), and your Holley 4150 will fit no problem.:)

Unfortunately the 4150 is part of my problem. It's a 750 with vacumm secondaries (which totally sucks) and is in such bad shape.... let's put it this way... there appears to be a drywall screw in holding the throttle cable onto the linkage. The genius I bought it off of said it works better that way.

I'm thinking of stepping up to a 850 cfm double pumper. Nice shiny finish. But I gotta put an electric choke on it. (The one I have no has NO choke whatsoever, and is a bitch to keep running when it's cold.) While I had it apart, I was thinking of putting new headers on (Dynomax Cerama-coats), new intake manifold, New Oil Pan, painting the block, heads, and intake red, redoing all the seals and gaskets, etc.

This is my first time doing anything major like that, so I'll probably be in here crying my ass off when I break something, we'll see.

How big is your engine? An 850 is a pretty big carb unless your running a big block. If you got a small block 350 or such you'd probably only want around a 650. I run a 650 Speed Demon vac secondary carb and it's a great carb. The vaccuum secondary model carbs tend to be a little better for everyday street use because the secondaries will only open up enough to meet the demand of the engine. You may want to check out the Demon Carbs website. Here's the link: http://www.barrygrant.com/ If you scroll to the bottom of the screen on the left you should be able to click on the heading "demon selection guide". This helps you select the proper carb for your setup. There's some good info on this site and most of this info would hold true for other carbs as well like Holleys, etc. :)
Oh yeah, you can click on the link under the pic of my Nova to check out the intake and carb I bought for my Nova, and some other crap as well.

Jim does have a big block, 454 if i remember correctly...

Yeah... 454 out of a 74 Monte Carlo or Chevelle (Mark IV). It has a P.O.S. 4160 on it, and totally bogs down if you nail it when it's cold. I'm not sure what all has been done to it, but the idle is so lopey that it almost sounds like it's going to stall when the RPM's are down around 750-800.

I was actually looking at going with an air gap intake with a 800 cfm Edelbrock, which was nice because it's like 1/2 the cost of a holley, but was told the vacuum secondaries are he culprit for the whole bogging down issue.

Are you telling me I am looking at the wrong setup????

i'm not sure about the vaccum leak, from few carbs i've worked with, bogging was usually a need for either more air or fuel... or a stuck accelerator pump...

ok so NOW I gotta get a new manifold, carb, wait... I already got a Pro-Flo air Cleaner. WTF????

Vacuum leak??? I have no vacuum, how can I have a leak??? I'm serious. From what I was told, it's cammed out and doesn't make enough vacuum to do a damn thing. No power brakes - not enough vacuum, etc. WTF???

I might as well by a bike at this point.

i thought you said something bout a vaccum leak... my bad, but secondaries are usually opperated by linkage not vaccum... so i'm confused what you were talkin bout...

Yes, I'd say due to the large cam you prob don't have enough engine vac to properly open up the vac operated secondaries. I don't have much experience working with an overly large cam or a big block for that matter, but I'd say switching to a mechanical secondary carb would prob be a good idea. My buddy has a Grand National with a 454 and he runs an 850 Speed Demon with mechanical secondaries and it works good. Most of his buddy's swear by them (mech secondaries). I don't know how large a cam he runs though, but I believe it's pretty big.:grinyes:

It's all starting to make some sense now.

okokok...

I know that one component can serious affect the performance of an engine if not mated up to the rest of the compenets properly, but....

Does it really matter for intake manifolds? I don't know what the hell is on mine off the top of my head, (weiand???) but I was thinking of replacing it with an Edelbrock AirGap manifold. Do I need to take anything else into consideration, like the carb, etc??? Should Holley's only be mated up to Weiands, and Edlebrock to Edelbrock, etc???:dunno:

The Weiand version of Edelbrock's Air Gap is a single plane manifold, "intended for race applications only". So I'm not sure if that's something I should be shying away from or not if I'm not REALLY going to race it. :frown: I just want to make any rice/mopar/ford owner ashamed that he picked an inferior vehicle manufacturer to pledge his allegiance to. :smooch:

And what the hell is the difference between single plane and dual plane, etc???:banghead:

Help???
yes they do matter

i think you would be good off witha edelbrock air gap, their suppose to be really good