[catalina_dream]

I would like to open a constructive discussion about when does an engine benefit more from a single plane intake vs. a dual plane. My car, along with countless others, run easily into the 12's with a factory dual plane and some of the F.A.S.T. guys run down into the 10's and even 9's with modified factory dual plane intakes. However, we all know that this is not really optimal. What are the operating parameters that point to the crossover point? Is it engine size, operating RPM, head flow, etc... Having a stock Formula (or GTO) hood really limits our options if we want to keep it, and I am trying to fully understand what the trade off's look like in regards to efficient performance potential. Thanks in advance to all that contribute to this post in a positive manner. Let's have fun with it.

-Kevin

[Tom Vaught]

Part of the deal (single plane vs dual plane) has to do with "How Much CFM and Fuel Does the Engine ACTUALLY NEED".

With a single plane intake and carburetor, each runner/cylinder gets to grab air and fuel from 4 barrels from Idle to MAX RPM.

With a Dual Plane Intake the 4 cylinders fed by one plane are happy up until that specific plane cannot flow any addition airflow thru One Primary barrel and one Secondary barrel.
At that point the engine tends to go into 'Governor Mode'. The engine will still make good power but it will not run as well as the single plane intake.

But you can "cheat" in some of the STOCKER classes if a spacer is allowed or a thick gasket with the divider partially removed.
Deal is to just get that bit more airflow from the additional air/fuel communication with the other plane of the intake.
Then you win vs the other guy.

Tom V.

[Dragncar]

Most Pontiacs make plenty of torque for the engine size. So I have always been a single plane guy.
Real engines have single planes. Not that I dont like a sleeper with a ported cast iron intake nobody knows about. Just not into duel planes.
Pontiac had one of the very first commercially available single plane intake(if not the very first) of any make. Nash Warrior.

[steve25]

I don't know about that single plane claim there Dragcar , as crossram Intakes are single plane also !

[dragracerx2813]

Originally Posted by Dragncar

Most Pontiacs make plenty of torque for the engine size. So I have always been a single plane guy.
Real engines have single planes. Not that I dont like a sleeper with a ported cast iron intake nobody knows about. Just not into duel planes.
Pontiac had one of the very first commercially available single plane intake(if not the very first) of any make. Nash Warrior.

The edlebrock tarantula was released in late 1970 and the Torker was released in 1970 for the Sbc. What year did Nash start making the Warrior ?

[Tiger Paw]

Tom V., Help me here. As far as single plane manifolds I think the M/T was first with crossram, Offy had dual 4 inline, Nash manifold was the first single 4, then came the Edelbrock tarantula type manifolds for Pontiac's.

Because Pontiac's are generally port limited, it's my opinion that they'll like single plane manifolds, because port velocity is high. I'm also a big fan of fewer turns in the intake tract!

We are talking race engines however. Street/ strip depends on a bunch of variables.

[ponyakr]

Since it is so easy to change intakes on a Pontiac engine, hasn't there been lots of intake testing done, both on the dyno & the strip ?

From what I've read. The dual plane worked best under 4000rpm, especially on 400 & smaller engines. Therefore, on mild to moderate street 400 & smaller engines, I suppose it's safe to say that a good dual plane would be best, for MOST idle to 4000rpm street operation.

But, again, from what I've read, 455 engines run just fine on single planes, since they have so much low end torque. But, it has been proven from testing that the original Pontiac Torker , made less power than the Torker 2.

But, a few of the tests we read about are a little confusing. Those that come to mind are the Jim Hand tests & the testing that Cliff has done. Jim's tests showed that a Performer produced the same ET as his iron intake, in his 455 street/strip wagon. But Cliff has posted that the Performer shut his engine down EARLY.

So, MOST now don't recommend a Performer for anything bigger than a mild 400 street engine.

http://www.silverstatepontiacs.com/j...rticles14.html

[ponyakr]

While on the subject of intakes, let me throw this into the discussion. The Torker 2 is made for square bore carbs. But, lots of guys, like me, like Q-jets. Also, lots of guys say that a spacer will increase performance on most low rise intakes.

So, the question is: Will a Q-jet work OK on a Torker 2, IF you rig up a spacer/adapter in the correct way ? If so, exactly what type & size spacer/adapter would be needed, along with any mods needed to the intake itself ? Maybe some type of hand porting/blending ?

I have a couple of 455's which both used a T-2 with a 750 Holley, which came on one of the 455's, in a beacket car I bought. I am thinking of putting my last 455 into my mid 80's Safari wagon, for street/strip duty. If I do that, I don't wanna run the Holley on the street. So, what is the best way to successfully mate a Q-jet to a T-2 intake ?

Yes, I have an iron intake. Also have a Chinese single plane. But, since there are plenty of T-2 intakes out there, and since this is an intake thread, I'd like to hear some ideas, especially from those, if there are any, who have successfully used a Q-jet on a T-2.

[Skip Fix]

A couple of personal experiences swapping a ported HO for ported (HO Racing guidelines) T1 on my RAIV 400 with a 288/292 SFT UD , T1 KILLED my bottom end even with a 4500 stall and dropped vacuum. No carb tuning could pick back up. It did pick up 2 mph. When we dynoed the RAIV with a milder 288/296 HFT a T1, T2 and HO all dynoed the same HP but TQ curves were way different.

455 ported E heads 259/262 solid roller motor. 850 Demon on the HO with adapter picked up over a Carb Shop modified Q jet. Swapped a T2 on idle was better and picked up 0.5 seconds! Ran 10-90s @123 weighing 3750.

[dragracerx2813]

Originally Posted by ponyakr

While on the subject of intakes, let me throw this into the discussion. The Torker 2 is made for square bore carbs. But, lots of guys, like me, like Q-jets. Also, lots of guys say that a spacer will increase performance on most low rise intakes.

So, the question is: Will a Q-jet work OK on a Torker 2, IF you rig up a spacer/adapter in the correct way ? If so, exactly what type & size spacer/adapter would be needed, along with any mods needed to the intake itself ? Maybe some type of hand porting/blending ?

I have a couple of 455's which both used a T-2 with a 750 Holley, which came on one of the 455's, in a beacket car I bought. I am thinking of putting my last 455 into my mid 80's Safari wagon, for street/strip duty. If I do that, I don't wanna run the Holley on the street. So, what is the best way to successfully mate a Q-jet to a T-2 intake ?

Yes, I have an iron intake. Also have a Chinese single plane. But, since there are plenty of T-2 intakes out there, and since this is an intake thread, I'd like to hear some ideas, especially from those, if there are any, who have successfully used a Q-jet on a T-2.

Years back a buddy of mine was using a Q-jet With a Torker 2 on a 455. He was using a standard Q-jet to square bore adapter. It worked pretty well. Most of the time a Torker 2 likes a spacer on it. So you kinda kill to birds with one stone so to speak. Now we never did any track testing to see if it made any difference . But the car ran very well.

[Tom Vaught]

Originally Posted by Tiger Paw

Tom V., Help me here. As far as single plane manifolds I think the M/T was first with crossram, Offy had dual 4 inline, Nash manifold was the first single 4, then came the Edelbrock tarantula type manifolds for Pontiac's.

Because Pontiac's are generally port limited, it's my opinion that they'll like single plane manifolds, because port velocity is high. I'm also a big fan of fewer turns in the intake tract!

We are talking race engines however. Street/ strip depends on a bunch of variables.

If we go back in Pontiac History you have some old Pontiac Dual Quad Intakes from the 50s.
Then you get into the early SD Intakes in aluminum (some made by Mickey Thompson) I was told.
Then you have the Crossram intake from Thompson that was actually a dual plane intake except that opposite side carbs feed the other side head. (No communication between each set of 4 runners).

Then you have the Edlebrock and Offy dual quad intakes. Edelbrock being a TRUE dual plane design and Offy being more of a single plane design with the "Windows" built into the manifold to allow sharing of the intake charge between all cylinders.
Factory cast iron Pontiac Intakes were for the most part Dual Plane Intakes.
Doug Nash did the first single plane Race 4 bbl intakes for Tom Nell. He did the dual quad intakes
(basically a front and rear dual plane intake with a communication passage between plenums). The intake could also be a Dominator IR runner intake.

Holley did the first open plenum single plane aftermarket "race" intake that was better vs the Factory Dual Plane HO Intakes.

So really all of this discussion DEPENDS on what time period you are ralking about.

Last but not least, a very few Z-28 Trans Am PONTIAC cross rams were cast up that resembled the chebby SB Trans Am parts and they were open plenum.

Tom V.

[ta man]

The guys running really quick with stock cast iron intakes...have much time and money invested into the intakes and are following class rules so its hard to see those guys doing any intake testing.

From my experience:

I tested a port matched rpm vs a port matched torker 2 years ago on my car. 3700lb mid 11 second 462 trans am with 3200 convertor and 308 gearing.
I was starting to hit a performance plateau with the combo...and many if not the majority of people thought the car would pick up et with the rpm. I did have a few people question "Why are you going backwards?"
The only difference between the intake use was I was able to use a one inch spacer on the Torker 2..vs no spacer on the rpm.
From first install the rpm felt flatter..it seemed to pull ok..but as far as low end power it felt slower. Track results confirmed it, my 60 fts were slower by almost half a tenth and mph down almost by 2mph and lost almost 2 tenths.
Once the torker 2 was reinstalled the previous performance returned.Fast forward to the following spring,I purchased another Torker 2 had a fellow board member do plenum and runner work to it. This intake picked up about a tenth and half and almost 2 mph..first time out.

Over the last 2 years I've also witnessed 2 other low 11 to mid 11 second cars with similar combos switch from well prepped Quadrajets and performer rpms to single intakes and Holleys and pick up 3 tenths and 4 tenths respectively. The fellow that picked up 3 tenths is a local Quad guru..and was a shock to me he switched, the other guy is my buddy Torquewar who installed a Torker 2 and a "Shaker" tuned Holley..he went from running 11.4's to 11.0's and a Cpl 10.9's.
I don't by any means want to start a "Quadrajet" bash..it is more a discussion of the intake use.

[joes455]

I welded a spacer on a tq2 ,2 reasons.1 for height ,2 was to get rid of that fwd tilt.

[lust4speed]

Just to muddy the waters a little more. My son's 462 Firebird engine was running a port matched RPM manifold, Holley carb, and 4" air cleaner. When I went to the Victor on my drag car my son adopted my old T1 intake with the 1" spacer. He had to drop down to a 3" cleaner to get the hood to close, but even with the Holley carb and shorter filter on the T1, the car went over a tenth quicker with nothing else changed. Not saying this was anywhere optimum, but even this combo picked up a lot over the RPM.

[steve25]

My findings are that on motors above 440 cid with decent flowing heads and shift points @ 6000 or better that the rpm Intake wants a big Carb, like 850 or even 950 to work as good as the T2 Intake with a 750 cfm Carb!

[Tom Vaught]

A 950 HP carb is actually closer to a 750 cfm carb in flow. Might have 850 throttle plates in the base but the venturi size is still 1-3/8" and that venturi flows 750 cfm at Holley's OLD Test Pressure of 20.4" of Water.

Now if you want to artificially bump the test pressure number up (test at 28" of Water like Barry Grant did then the number will be higher).

A 850 CFM Carb will flow 850 cfm at Holley's OLD Test Pressure of 20.4" of Water and will flow closer to 1000 cfm at 28" of Water.

I guess if you want to race numbers with different test pressures, go for it.
I will stay with Holley's old Carb flow testing standard (based on the NACA testing points) used years before Barry Grant and Smokey came up with their 28" Water number for testing.

Tom V.

[3fastgtos]

Ok guys I'd like your opinion on an intake for a current street motor I'm building for my new daily driver. It's going in a '69 C10 2WD with a T56 and 3.73 gears.
It's a 9.5-1 .030 over 428, ported 614s (315@.650) RPM 4.000 crank, bushed Eagle 6.7 rods. Cam is undecided at the moment but probably in the .550-.600 lift range and duration 240-260@.050 range. Billet MSD distributor and either a 780 Holley or MSD's EFI.
My gut tells me a modified RPM manifold since the bulk of the driving will be below 2500 rpm. I'd like to say I'll never race this but I'm easily provoked:-)

[PAUL K]

Originally Posted by 3fastgtos

Ok guys I'd like your opinion on an intake for a current street motor I'm building for my new daily driver. It's going in a '69 C10 2WD with a T56 and 3.73 gears.
It's a 9.5-1 .030 over 428, ported 614s (315@.650) RPM 4.000 crank, bushed Eagle 6.7 rods. Cam is undecided at the moment but probably in the .550-.600 lift range and duration 240-260@.050 range. Billet MSD distributor and either a 780 Holley or MSD's EFI.
My gut tells me a modified RPM manifold since the bulk of the driving will be below 2500 rpm. I'd like to say I'll never race this but I'm easily provoked:-)

4" stroke engines work very good with the T2....I'd go with it.

[S/st 54]

Since we are in a technical discussion, I was wondering if anyone has used 2 torker 1's cut in half and had the 2 back halves welded back together? The back half of those intakes are huge/open quiet a bit and seem like they would work really well and seem like they would need minimal "porting" to get it to work..
Old school badA$$ if you ask me.


I'm sure there are better intakes than that available today but I was wondering if anyone has tried it and what were the results?

[Skip Fix]

Originally Posted by 3fastgtos

Ok guys I'd like your opinion on an intake for a current street motor I'm building for my new daily driver. It's going in a '69 C10 2WD with a T56 and 3.73 gears.
It's a 9.5-1 .030 over 428, ported 614s (315@.650) RPM 4.000 crank, bushed Eagle 6.7 rods. Cam is undecided at the moment but probably in the .550-.600 lift range and duration 240-260@.050 range. Billet MSD distributor and either a 780 Holley or MSD's EFI.
My gut tells me a modified RPM manifold since the bulk of the driving will be below 2500 rpm. I'd like to say I'll never race this but I'm easily provoked:-)

Sounds a lot like the motor I've collected parts for my 65 GTO project. I have 6.8 rods though.

Please flow your heads before you pick a cam! RAIVs with any porting on the exhaust side have a very high E/I ratio and do not need a "normal" duration split type cam. There is a reason why the RAIV SS guys like John Angeles, stock guys like John Schloe use a single pattern cam. My street /strip RAIV 400 liked a "reverse split"-I tried 5 cams in that motor. 242/236 @ 0.050. That 400 really preferred a dual plane to a single plane but it had less CI than yours or my planned motor.

You also need to not go too big on exhaust especially if using a muffler system(since a street car I assume so). That exhaust port can fklow backwards and give you reversion issues if the exhaust does not have enough velocity.