Will the real intake please stand up?

[littlecampbell]

I was reading this thread on another (ahem) Mopar site...Have a listen...."If your going to upgrade from a stock 340 intake, why bother with a dual plane? You'll pick up negligible horsepower and probably lose low-end torque with an Air Gap-- Get a single plane and be done with it. Air Gap intakes(any dual planes) are alot of money for an intake thats only marginally better than stock"....I was under the impression that a dual plane will pick up low end torque and lose some high rpms....other way around with the single plane? How could I possibly lose low-end torque with an Air Gap or any other dual plane over a stock intake?.....Hmmmmmm...

[6 packin]

That guys sniffs to much glue! If one switches form a stock 340 intake to a Edel Performer RPm or Air gap he which is a duel plane piece will pick up maybe 25 Horse or more depending on cam and other things. The air gap is a good idea. The Torker II will make less bottom end torque and less Top end power. This has been proven in various mags. The Torker II thought to make more top end power does not.... The air gap is a good piece. There are many advantages to running that intake over the single plan. Better signal to the carb. Better vacum for the engine. The list goes on.............................

[caveman]

I agree most guys should use a Dual Plane on the street,hotter street/strip cars can use a single plane.The list goes on,,LOL

[383-man]

I used a Torker single plane on my mild 383 with the .484 cam and 3.91's. Best #'s with it:
12.41 @ 110
1.82 60 ft
7.95 1/8

Swithced to Performer RPM dual plane on my street car and ran:
12.31 @110
1.77 60 ft
7.87 1/8

So you can see the low end is much better as my 1/4 et is a tenth quicker with the same mph and my 60 is 1/2 tenth better and 1/8 is almost a tenth better. Ron

[dave571]

The guy you quoted needs to do more expensive drugs. Get off the cheap stuff.

Anyway, recent reserch and testimonials have shown that a modern dual plane intake is superior in every way to single planes (like a torquer) I've got a customer who switched his 340 from a single plane to an air gap, with results much like the earlier testimonials.

My only experience with single planes, is that they are not as crappy for low end as people say(depending on what you've changed from)

example. 77 ford 3/4 ton 4X4 . 351M motor. It was my snow plow truck. In any case 351M's are almost all 2 bbl(especially in trucks). I wanted a 4bbl manifold, used. All I could find was an edelbrock single plane. I figured it would be really crappy on a low rev/torque motor, with a small/stock cam, but how could it be any worse than the factory 2bbl??

It turned out very good. Good throttle response, better torque, more top end power. Of course the already terrible fuel economy went straight through the toilet but, Oh well.

[pishta]

383-man, what was your trap RPM? The Torker likes to breath and if you are running a 3.91 rear in a 1/8 time trial, or 1/4 milers you are hitting the traps at like 4500 RPM? (guessing) Id like to see the same comparison with a real set of drag gears, like 4.56's or better. Im in the same boat. I got a torker on a 451 with 3.23's but I only weigh 2850 or so, so the low end wont hurt much.

[451Mopar]

You have oversimplified dual plane vs. single plane.
There are small runner/plenum single plane intakes like the Holley street dominator and edelbrock streetmaster that make good low/mid power, and there are large runner/plenum dual planes like the edelbrock performer RPM and Indy dual plane that make good power from the low/mid to upper rpm range.

There are many different designed intake manifolds for different applications. The stock cast iron 4-bbl is a decent manifold for under 5,000 RPM, and some aftermarket aluminum street intakes are sometimes very simular to the stock intake. On my mild 383, I installed a Weiand 8008 dual plane which is very simular to the stock intake and I din't notice much difference in performance. I later installed a single plane intake and the car was quicker when racing, but I did notice a loss of low end torque.

From the magazine tests ran on the performer RPM, it outperformed almost every intake from about 2,500 RPM to about 6,000 RPM. The smaller runner Performer was better to about 3,000 to 3,500 RPM, but gave up upper RPM power.
The Mopar M1 single plane did pretty well in the comparison even though it was a single plane intake. It make more upper RPM power, but could not make the low end torque like the dual plane design of the Performer RPM.

With a hot street/strip setup that has gears and a 3,000+ stall converter and sees over 6,000 RPM, the single plane design should have a HP advantage, but for most milider street (sometimes strip) engines that rarely see 6,000+ RPM and have mild gears and lower stall converters, the torque of the dual plane design can make the car more responsive on the street and sometimes even quicker in the 1/4 mile.

[littlecampbell]

451Mopar.....I think that explains it best. What about 4spd 340 Dart with 3.91s, 484cam,750 AFB? Mostly street. Thanks for the replies...straightens this out once and for all!
In "How to Hot Rod Small Block Mopars" by Larry Shepard he says not to use a spacer with a dual plane. On an earlier thread it seems to me that Cuda66273 said to use a 4 hole spacer with an Air Gap ...Hey Don are ya gettin sick of seafood yet? Ill send the Mission schedule when its posted, should be soon.

[rumblefish360]

"In "How to Hot Rod Small Block Mopars" by Larry Shepard he says not to use a spacer with a dual plane. "

What page? And a open spacer is what I believe he is taking about. A 4 hole unit would be the one to use in apps.
On the other site, I believe the fella was saying that if you switch to a RPM/Stealth, you would lose power as compared to the stock unit. This would be true with a mild cam. The power band of the RPM intake listed starts at 1500.
Single planes produce more HP in the upper RPM band in radical engines.
On a street/strip engine, IMO, every single plane intake takes a back seat to a good dual plane intake.
On the strip, theres 2 manifolds of choice to go fast. A single plane or tunnel ram.

[383-man]

Pishta I dont know my trap rpm because I dont have a tach in the car. I can tell you its almost peaked out and I would guess its about 5500 rpm as I use single Crane valve springs with a dampner. Here is my car with the 26" tall McCrearys I use at the track. Ron

[littlecampbell]

Rumblefish...on page 140 Larry says "They should only be used on race cars with single-plane intake manifolds. You can install them on dual-plane intakes, but you are better off to switch manifolds." Also "As a general rule the four-hole spacer helps torque while the one-hole spacer helps top end".
Any ideas why he recommends not to use them on dual-planes?
This sure is a very informative piece of reading (even for a slow learner such as myself )

[rumblefish360]

OK, gotcha.

On useing the spacers, on a single plane, the bennifit is a few HP. This is something you should prove on the strip. It's no secert that big gains can be found with them. The wrong one can cause a lose.
Some single plane inatakes, and or the build up of a combo might bennifit from raising the carb up.
On the dual plane intakes, the use of a spacer wil gain some HP, in an open unit and maybe some torque in a four hole unit, but the real gain is in switching the intakes over to a single plane.

Keep in mind this was writin before the introduction of the stealth and RPM intakes where the best dual plane was topping out at 6000 on it's best day.
These 2 intakes changed the game around.
A spacer is worth checking out.

[littlecampbell]

Okay Rumblefish, I see this was published in '89...So no problem with a 4 hole spacer under an Air Gap? Also says may have to rejet carb before any gain from the spacer is found.....Thanks for the input

[RogerH]

We typically see power gains with both one and two inch spacers. If you don't see any gains with them, then you most likely have another power restrictor with your engine, and after that is found and upgraded, then you will see power gains with a spacer.

[gotcha]

LC.....I have tried just about every intake available for the SB Mopars......and as a dual purpose intake, nothing matches the performance level of the old LD340 or Performer RPM Air Gap.
(Dual planes)

The Holley Strip Dominator is the best single purpose (racing) single plane..single four barrel intake ever produced....(my opinion...and time slips don't lie.) The M-1 is almost a carbon copy of the Strip Dominator.

For pure inexpensive dual purpose performance.....the 72-73 cast iron Thermoquad intake modified for square flange carbs is an excellent intake....but very heavy.

Spacers work as Roger said. I use Wilson on the race motors and a home grown phenolic 4 hole on the street/strip stuff.

[451Mopar]

littlecampbell, with a mostly street driven 340 with 3.91:1 gears and the Mopar 284/0.484" cam, I think (in my opinion) that the Performer RPM air-gap would be the best intake. The 750 cfm carb should work well with the setup too.

[pishta]

Littlecampbell, I had the identical setup on my 340, 3.91's edelbrock Ld340 (close to an RPM) 484 cam, headers and a 2800 stall, man that thing would haul ass. If I had better tires in the back, meaning more meat, I would have been dangerous (considering I still had 10 inch drums all around) I too had the Strip Dominator and it was a sweet intake. I didnt notice too much low end loss with it and it would floor you at about 4000 RPM. LD340 was pretty smooth all the way to 6K