[rad400]

72sportconv, is the 350 in your car now a Pontiac or a chevy, just was wondering cause you asked about the air gap. If it is a chevy, the trans will not bolt up to the Pontiac 455.

[Cliff R]

Yes, I tested one on the 428 engine, along with the iron and RPM intakes. It was not a stock unit, but modified exactly like our iron intake, will all of the material between the front and rear holes removed, gasket matched and we also removed any and all bumps/castings flash, etc, in the runners.

We tried it with and without a 1" spacer, it was the intake used to break-in the engine on the dyno and make most of our initial pulls. It made less HP than the iron intake and the RPM. Nearly as I can remember (don't have the dyno sheets in front of me) the best pull was 489hp, RPM 491, iron intake 497. The HO intakes are very similiar to the iron intakes, but shallower in the plenum, and the runners may be slightly smaller as well? It ran close to the other intakes, but still made less power across the rpm range where the dyno could record it. Also keep in mind that this was the "reproduction", not an original.......Cliff

[RAJNWDY]

NOW BOYS, calm down!

I think all the info here has been benificial to who ever reads the tread. I too have done manifold testing on my car, but I won't get into it here.

My choice of intake on "MY CAR WITH MY SET UP" was the TII with a Holley 750 VAC secondary. But on other engines with other cams with other heads and rear end ratios, it may not work!!!

But I don't drive by the "seat of my pants" but by what keeps "MY PANTS IN THE SEAT"


HAR DEE HAR HAR from rdrr

Happy 2008 to all

[Kyflier]

Hey Cliff, is your cast iron manifold modified like the one in the Jim Hand book? Or do you have some "special" tricks done to it?

[Thomasmoto]

72, Do you know for sure what carb you are going to use? If so, what is it? I think we can better advise you from there.
David

[Overkillphil]

Warbird, the HO/RAIV intake, while good suffers from some minor changes in order to make the exhaust crossover removable. The subtle changes made it a slightly weaker performer against the iron intake. That coupled with the fact that they are scarce is the reason we don't see to much of them in use.

And forget the repop from China, very poor quality.

Cliff, did your testing of the Tomahawk (where it performed on par with the RPM) include a spacer plate?

[1971WARBIRD]

Originally Posted by Overkillphil

Warbird, the HO/RAIV intake, while good suffers from some minor changes in order to make the exhaust crossover removable. The subtle changes made it a slightly weaker performer against the iron intake. That coupled with the fact that they are scarce is the reason we don't see to much of them in use.

never even thought about where they made the crossover removeable affectting it,duh.i have a factory replacement cast in 75 that i may play with later.it has cleaner ports that the 71-72 casting i have.

[Cliff R]

"Hey Cliff, is your cast iron manifold modified like the one in the Jim Hand book? Or do you have some "special" tricks done to it?"

It is similiar to the one Jim Hand uses, but more heavily modified at the flange to the near identical size/shape as the rpm intake, and we added enough material for both bolt patterns to test Holley and AFB style carbs at the flange without an adapter/spacer.


"Cliff, did your testing of the Tomahawk (where it performed on par with the RPM) include a spacer plate?"

We only tested the Tomahawk once on my 455, at the track for the HPP "Shootout". I made several runs with the iron intake, bolted on the Tomahawk, then added a 1" spacer.

With or without the spacer it gave up nearly a tenth is 60' times, but picked up 2mph with the 1" spacer, and ran within .02 seconds of the iron intake.

Without the spacer is was off about a tenth overall, nearly as I can remember?......Cliff

[A.W.Dille]

Well since our cars are similiar in weight, mine being a 71 GTO but with a 400 (and at the present running a 3 speed until I get my 4 speed fixed) I also would recommend the iron intake as I have found it to be by far the best (in my application anyway) to either the Performer and my Torker. With the Q-jet I am presently running the throttle response is much smoother and drivability is much better, even more so than when I was running spreadbore Holley's. At the track when I was running 3.55 gears the best time with the Performer was 8.72 (all 1/8th mile times) with a 60ft of 2.02. With the Torker I ran a best of 8.52 with a 60ft of 1.92 and with the stock iron a best of 8.46 (after busting a motor and trans mount and having to granny shift) with a 60ft of 1.806. The engine is exactly the same, stock 400 block, 670 heads that have stainless steel valves and a 3 angle valve job with a Lunati BMII cam (.490 lift, 230@.050 with a 110 LS and an intake centerline of 104 degrees. The only differences were the carbs, With the Performer I ran a 6210 650cfm Spreadbore Holley and with the Torker and stock intakes a 6213 800 Spreadbore Holley. Now I'm not saying the Performer is a bad intake, it just didn't work for me now matter what the state of tune was. In fact it ended up on a 350 Pontiac with a mild cam and ran great. JIm Hand and Cliff have done quite a bit of testing over the years and I fully respect what they have to say, and I think that both will agree with me that every engine and combination is different and no matter how close two engines may be what may work real well on one may not work as well on the other. But for a street engine or an engine that may see some limited action at the track I myself recommend the stock iron intake, Others here may disagree with me and this is my opinion only but I know what has worked the best on my GTO so far, for the way my current engine is set up, I have found the best feel so far with the Q-jet and iron intake.

[Cliff R]

In addition to intake manifold testing, we have also done quite a bit of dyno and dragstip testing with carburetors, and have found very little difference in ET/MPH between the different brands/makes/models, once they were dialed in exactly for the application.

FWIW, the only two parts that we were unable to effectively dyno and drag strip test, were the Edelbrock Performer intake manifold, and an Edelbrock Performer 750cfm AFB "clone" carburetor.

By far and above those two parts were the WORST items I've ever bolted onto my 455 engine.

We tuned the 750cfm Performer carb to DEATH, with an Edelbrock tuning kit, and could NOT get the stumble/hesistation/bog out of it, no matter where it was calibrated. I even obtained a second carb at one point, and the results were identical.

Same with the Performer intake, knowhere near enough intake for our engine. As a disclaimer, I will say again that some folks are able to use these parts and are fine with them. Simply put, neither one was up to par for effectively feeding our 455 engine at 514hp and nearly 600ft lbs torque production. They may and obviously do fair much better on smaller/lesser powered engines, and cars that don't run nearly as fast....Cliff

[AGTO8U]

You guys sharing your information and experiences is much appreciated! I have an RPM intake to be installed on a 433 with 246/254 cam, 10.5compression, 250cfm iron heads, 750carb. I expect this to have around 450hp? Question is would it be beneficial to cut down the secondary divider plate 1/2" on the rpm intake or just leave it as original? Car weighs 3400lbs.

[Tim Corcoran]

The best intake depends on your performance level. Depends on your compression, cubes, cylinder head flow, cam type and size, weight of car, etc... For most mild builds the factory intake is hard to beat. An awful lot of people are going slower because they installed an aftermarket intake manifold. Some are going faster with a ported Holley or a Victor. Even fewer are going faster with custom fabricated sheet metal intakes. If you have an 8 second car I don't think you will go faster with a stock iron intake, and if you have a 13 second car I don't think anything will beat a stock iron intake in most cases.

Tim C

[Geoff]

Cliff,
I was tossing your the hand grenade back to you............
Out of curiousity: up to post #14 [yours] no one, repeat, no one mentioned any HP or TQ figures to support their respective choices of manifold. Yet, you singled out my comments because I quoted no HP figures. Yet again, you totally misread what I said. I used the phrase' best overall performance for a street driver'. The phrase encompasses more than outright HP & TQ figures, but also throttle respons, smoothness, etc. The PEAK HP & TQ numbers you quoted are of little use for a 'street/weekend driver'.
Bottom line is, my comments about the equality of the Perf & iron intake are supported, using YOUR criteria, by two well known Pontiac identities: Jim Hand & Pete Mc. Jim recorded the 1/4 mile test results in his book of both the iron intake & the Perf. Times & mph, no difference between the two. PeteMc removed a stock iron intake & replaced it with a Perf & picked up 13hp with a mild 455 [ Qjets both cases ]. So just because the Perf didn't work on your engine, doesn't mean they are no good. A flick through these forums will quickly show otherwise.
I am well aware of yours/Jim's manifold mods & spacer. I got the impression from the original post, #1, that bolt on parts were what the owner wanted. To modify a stock intake intake requires tools that some folks don't have, or don't want to go to that much trouble.
Yes, you mention less exh duration & lot's of timing at idle that AGAIN even though it has absolutely NOTHING to do with this thread. Since you did mention them..........Yes they both work! A look through the archives will tell the story.

[Cliff R]

"I found the Perf with a 1" divided spacer gave the best overall performance for street driving. Also tried the stock iron intake with the same spacer & could tell no difference from the Perf intake, except for the weight!"

"Cliff,
Who cares diddly squat if your dyno & drag strip results 'do not concur' with my seat of the pants results."

Geoff, thanks for a much more civilized answer in the last thread, but you still, as always, provided ZERO direct information from any sort of accurate testing on YOUR vehicle to qualify ANY OF THE INFORMATION. So, from where I'm sitting, it means "diddly squat".....and here is why:

About 5 years ago we moved the 60919 camshaft from 109ICL to 111, 113, 107, then back to 109. The car was street driven, and drag strip testing after each camshaft movement.

It "felt" the best at 107ICL, smoother throttle response just off idle, and I was fully expecting the best 60' times and fastest runs......it ran the SLOWEST for all runs at 107ICL

We tested a Street Dominator intake manifold. By the "seat of my pants" if "felt" much stronger across the rpm range, expecially in the upper mid-range and top end, than the iron intake, we LOST nearly .2 seconds at 2mph at the track.

I repeated the testing with a Tomahawk intake, it "felt" fantastic on my engine, we were fully expecting improved track numbers, it ran SLOWER than the iron intake by about a tenth, and still went .02 seconds SLOWER with a 1" spacer.

I tested 4 different spacers on my intake, 4 hole, fully divided, fully open and semi-open. It "felt" the best with the 4 holes spacer, and about as good with the fully divided spacer. AGAIN, throttle response right off idle was excellent, however, at the track we ran the fastest with no spacer at all. The only spacer which even came close was the semi-open spacer very very similiar to the one pictured in Jim Hand's book.

We backed up the spacer testing at the dyno, and low and behold, the iron intake made more power with no spacer at all, vs the semi-open and fully divided spacers.

We tested the Performer intake, as mentioned, and it "felt" FANTASTIC just off idle, and for any very light throttle openings. It all went to CRAP when we tried full throttle testing, as mentioned previously.

My point, and something that you should SERIOUSLY consider when "qualifying" parts, DO NOT believe everything that you read, and your "seat of the pants meter" is probably NOT nearly as accurate as you think it is.

If/when you get time, I would be VERY interested in seeing some addtional direct comparisons in dyno and even moreso, track performance between some of these parts that you are posting results about?

As far as folks caring "diddly squat" about what we are doing, I agree, some folks could care less, in contrast, there are a LOT of enthusiasts that don't get caught up in all the BS, and want to really know what works the best. If no-one gave a crap about how any/all of these available parts really worked, EVERYONE would have an Edelbrock Performer intake, Edelbrock Performer camshaft, and Edelbrock Performer carburetor on their engines, because Edelbrock tested that stuff, and it works....right?........Cliff

[Motor Daddy]

If a different intake shifts the power curve up or down the RPM scale and you don't change gears and launch and shift points to compliment the change of torque curve the test results are inconclusive.

[Cliff R]

MD, our launch rpm is 3500rpm's, probably higher than most of the street Pontiac powered cars owned by folks reading these threads.

We do vary shift points, time permitting. We have found that raising the shift point does NOT always improve ET or MPH, and when it does, the difference is not nearly as much as one might think.

One of the manifolds we tested, the Street Dominator, was left in place for several dragstrip outings, swapped back and forth, etc, as I was certain that it's "felt" improved performance would have it outrun the iron intake at some point. No matter where we shifted, between 5000 and 5800rpm's, it still ran nearly 2 tenths and 2 mph SLOWER than the iron intake.

I consulted with Jim Hand, about the results, and they pretty much concurred with the testing he did with single plane intakes. He described the situation as this:

With the single plane intakes we "feel" a strong rush of power in the upper mid-range, upper rpms/top end. This is quicky interpreted as a performance gain, when more times than not we are simply feeling a "transition" between LOST performance at lower rpm's revving into the "ideal" power range of the intake being tested.

In other words the shift in power was also associated with a LOSS in power at lower rpm's, which means slower launch, worse 60' times and MORE TIME REQUIRED to get into the "sweet" spot, or ideal power range from the single plane intake.

As we found out with the Tomahawk intake, which is more or less a highly refined SD intake, it actually made MORE power as we picked up nearly 2 mph on our runs. However, the strong top end charge did NOT make up for loosing nearly a tenth on the starting line/60' times, so the vehicle still ran SLOWER in ET, or actual vehicle performance.

I would also add this, street testing, at least with my own vehicle is HIGH FLAWED, since the DOT tires will slip some with full throttle runs. This allows the engine to rev into the good power much more quickly, and gives the driver of the vehicle a feeling of greatly improved performance.

At the track, where the tires do not spin, the launch feels "soft", and there is a noticable time lag until the engine finds the ideal rpm/power range provided by the single plane intake(s). This shows up on the time slips as slower 60' times/LOST ET, even if we run more MPH provided by a stronger top end charge.

I hope this helps to explain the situation, as to why I hold very little value in simply testing intakes, or any other parts simply by the "seat of your pants", it will lie to you nearly every time!.......Cliff

[Motor Daddy]

Cliff, I'm not suggesting seat of the pants testing for anything. It's a very long and drawn out process to explain what I am saying, as I'm sure you have probably seen for yourself on the torque/hp debates that I get into on CP, PY and Speedtalk. I'm not arguing for fun, I assure you. I am trying to get my point across that when shifting power up and down the RPM scale it may appear that the greater torque curve will win, and that peak HP is relatively useless. Nothing could be further from the truth.

Lets say for instance that you put a Victor Intake on your engine. As we both know, the power curve will be shifted to a higher RPM range. That means peak power will occur at a higher RPM. That also means that since the curve is shifted higher the lower portion of the curve will be lower as compared to a smaller cam, dual plane intake, small headers, and a greater CID. You are shifting the power band to a higher RPM. Look what happens to the numbers in the following example:

700 lb-ft at 3,000 RPM using a 3:1 gear is 2,100 lb-ft at the axle at 1,000 axle RPM.

400 lb-ft at 10,000 RPM using a 10:1 gear is 4,000 lb-ft at the axle at 1,000 axle RPM.

Both axles are spinning at 1,000 RPM and they both have the same size tire and the same vehicle. Which one do you think will increase MPH at a greater rate?

Now look what happens when you keep the gear and RPM the same, and only change the torque by shifting the torque curve higher:

700 lb-ft at 3,000 RPM using a 3:1 gear is 2,100 lb-ft at the axle at 1,000 axle RPM.

400 lb-ft at 3,000 RPM using a 3:1 gear is 1,200 lb-ft at the axle at 1,000 axle RPM.

When you shift the power you MUST CHANGE THE GEAR AND RPM to take full advantage of the shift in power.

I'm not suggesting it's easy, cheap, quick, or fun to change gears, but I will guarantee you that 400 lb-ft at 10,000 RPM using a 10:1 gear will accelerate at a greater rate. Running out of RPM and having to shift is the downer. If you don't run out of RPM (hit redline) before the other guy you will destroy him.

Testing a different intake and shifting the power and then keeping the same gear is self defeating and produces test results that are inconclusive.

[tpssonic]

What confuses me is Jim Hand's article #14 which gives the following results on his mid to high 12 second Poncho wagon spinning at approximately 5300-5400 rpm. The below are compared to his cast iron intake with no other changes:

* Pontiac Aluminum
HO Lost .08 sec. and ,4 MPH

* Edelbrock Performer
No change in ET or MPH

* Edelbrock Performer
RPM Lost .05 sec. and .5 MPH

* Edelbrock Torquer II
Lost .0l sec. and .1 MPH

* Edelbrock Torquer
Lost .29 sec. and 2.85 MPH

* Holley Street Dominator
Lost .25 sec. and 1.9 MPH

How can this be explained? These are very different results. Could it be that EVERY intake/motor combo must be tested individually and that NO blanket statements (e.g. Brand X model Y is best/not best intake for a low-rpm 455 engine) about intakes can be made without any great certainty?. In other words, are Cliff's and Jim's 455 motor combos enough different enough that the Performer results are significant (yet similar enough to support similar cast iron intake performance?). I am really curious.

I am in a similar situation where I am presently building a 455 (stock #96 heads) with a mid 230's (at 050") low .500 lift roller hydraulic cam and I have four new intakes from which to select: a Performer, Torker II, Torker I and a Doug Nash Magnesium (single 4 bbl). I have a 800 Q-jet or a Holley 850 DP to set on the intake.

[Jim Hand]

Quote from Motor Dadddy:
"Testing a different intake and shifting the power and then keeping the same gear is self defeating and produces test results that are inconclusive."

That statement is absolutely incorrect!

The tests both Clliff and I have made are to determine what a specific intake does on OUR cars. They are not intended nor performed to discover all aspects of any intake. We don't care what gear is required to optimize any intake if that intake slows our cars down! And we most certainly won't permanently install any intake if it requires a host of changes to equal or better what we already have on our car.

We don't test intakes in order to determine what or how many parts would be required to optimize performace with any intake on our cars. If it performs worse on our 5500 RPM engines, that is what we report. Then, anyone with similar 5500 RPM engines will have an idea what the intake would do.

If you think each intake should be tested for its optimum application, I suggest you get started testing in that manner and report the results to the board. Meanshile, we will continue to make practical tests and report our results. And probably continue to have very respectable performing cars because of the sensible comparisions!

Jim Hand

[1971WARBIRD]

to really throw a wrench into things.i understand the strip street thing,but some are guys asking for mostly street cars.it would be nice to see 40-60 passing test,20-40 responsiveness,fuel usage at 65 mhp,real street situations.i know it can't happen as to many things to test and none of us could afford to do it.just thinking that is what some are asking about.