intake question

360 small block, stock dish piston bottom end, 587 heads, comp xe274 cam,2800 stall,reverse manual automatic,3:55 gears..... street driven car... would intake choice matter? i have a Weiand Stealth, but i have always wanted an AIR gap... also have an eddy performer rpm i can pull off my 318.... which intake would be better or would you really notice a difference as they are all dual planes and just cruising with occasional burnouts.. no race...

Ive got an action+ which is similar to the stealth on my 360 magnum and an airgap on my 360 in my valiant and to be fair im not sure you could tell that much of a difference. If you got some money to throw away might give it a shot and let us know what you think.

Jake

texas360 said:

360 small block, stock dish piston bottom end, 587 heads, comp xe274 cam,2800 stall,reverse manual automatic,3:55 gears..... street driven car... would intake choice matter? i have a Weiand Stealth, but i have always wanted an AIR gap... also have an eddy performer rpm i can pull off my 318.... which intake would be better or would you really notice a difference as they are all dual planes and just cruising with occasional burnouts.. no race...

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It’ll show on the dyno and the strip but the seat of the pants a may not be so sensitive to the minor increase.
If you have the intakes already then the choice between the RPM & the Stealth or Action Plus, go with the RPM.

Home porting the Weiands go a long way....

Does the performer RPM come in different port sizes, cause if you have the one with 318 size ports, that'll limit your 360. I actually don't know if they come in different sizes, but that might make the decision between the two you've got for you

68Valiant225 said:

Does the performer RPM come in different port sizes, cause if you have the one with 318 size ports, that'll limit your 360. I actually don't know if they come in different sizes, but that might make the decision between the two you've got for you

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The regular Edelbrock Performer has smaller ports. The Performer RPM and Performer RPM Air-Gap are the same internally. The Air-Gap doesn't have a heat crossover, so it might be more tempermental on cold start-up and colder months. As mentioned by rumblefish360, a Stealth or Action Plus would be good, possibly more economical choices. LD4B or LD340 as well, but often pricey.

Hard to beat the air gap for a street cruiser.

The Stealth has 273/318 ports that can be opened to 340/360. Was yours opened up?

I say stay with what you have. 1) You have it. 2) It's a damn good intake.

I agree. Can you port the intake. You just need some machinist die and a scribe to mark out the gasket size and start going in on it with a die grinder and buts as deep as possible.

Combo dependent, adding a open spacer on a dual plane helps from the mid to the top end. Milling the divider is a very similar move but will also help in getting the die grinder bits in the plenum area.

The Weiand’s are capable manifolds and get really good when ported. While nothing beats the RPM now, but since you have the Weiand now....

IMHO - If you are going to remove the separation in a dual plane manifold it defeats the whole point. In that case get a single plane manifold and lose low end torque for better high end hp. If this is as described - a performance street cruiser and you want low end response that you can feel when you punch it, don't screw around with you dual plane separation. The opposite would be true if you are going drag racing or concerned with top end Horsepower. The Stealth that I have has big ports, but I bought it used so it may have been tinkered with... Is there a 273/318 and 340/360 version of that manifold? Gasket matching on the manifold and heads is always a good thing like mentioned above, but better to have small ports into big than big ports into small so don't open the ports in the manifold way up and then have a lip where it hits the unmodified head ports.

@str12-340 I agree to a point. Having owned and driven extensively a SB 4spd with a stock and then modified LD340, depending on the camshaft used and rpm band sought, the milled divider is a good move. I’ll state right here and now, it’s best with big cams. Not the one he has. It was a mistake for me to mention that with his cam size. A spacer would be the right move if hood clearance allows it.

str12-340 said:

IMHO - If you are going to remove the separation in a dual plane manifold it defeats the whole point. In that case get a single plane manifold and lose low end torque for better high end hp. If this is as described - a performance street cruiser and you want low end response that you can feel when you punch it, don't screw around with you dual plane separation. The opposite would be true if you are going drag racing or concerned with top end Horsepower. The Stealth that I have has big ports, but I bought it used so it may have been tinkered with... Is there a 273/318 and 340/360 version of that manifold? Gasket matching on the manifold and heads is always a good thing like mentioned above, but better to have small ports into big than big ports into small so don't open the ports in the manifold way up and then have a lip where it hits the unmodified head ports.

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Yup. Once again, the magazines and technical books and gurus convince people to do things not necessarily in their best interest. The removal of (or trimming) of that center divider (in most cases) only works to enhance upper RPM torque and power. Usually not beneficial for the street. Also, unless you're really good with "whatever" tool you use, you'll dick up an otherwise fine intake. Just because you see someone else do something doesn't always mean it's good "for you".

RPM IS FINE SO IS THE WEIAND if it has the right port size , don't think you will gain much with the air gap . I ran an air gap on my 340 and it made no difference over the stock intake except start up when it was cold , took a while until it warmed up and ran well

The air gap is better than the stock intake for two reasons. One its MUCH lighter. Two, runs cooler without the heat crossover and the air gap. Other than that I agree, its pretty much the same design as a stock 340 intake. But hey, a stock 340 intake is a damn good intake except that its a porker.

I used to run the AirGap from May-long weekend to either;September long-weekend, with Zero starting or running issues.
Between those dates, I ran a 4bbl-smoggerteen, all winter long, with studded Mud and Snows.

But with 8/1 compression and 3.55s it's a good thing you got that 2800TC! If your rings are not new,I would run it with whichever intake has the smallest volume ports, and a carb no bigger than a 650. And if it was me it would be a 650DP.

The weiand intake port opening is small on both the + and stealth intakes. Roughly the same size (1.00x1.96) as the performer 318/360 (.097x1.95)

How does the bad performance of the window opening play here?

crackedback said:

The weiand intake port opening is small on both the + and stealth intakes. Roughly the same size (1.00x1.96) as the performer 318/360 (.097x1.95)

How does the bad performance of the window opening play here?

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I guess that would depend on how much the engine demands. If it demands more than the port window can deliver, then that certainly that would have an effect.

But the 318 vs 340/360 port comes up ALL the time and these two intakes are recommended quite often for the 340-360 heads... I'm confused, they have some of the smallest ports of ANY SB mopar alum performance intake....

The port size thing can be a HUGE red herring.

texas360 said:

360 small block, stock dish piston bottom end, 587 heads, comp xe274 cam,2800 stall,reverse manual automatic,3:55 gears..... street driven car... would intake choice matter? i have a Weiand Stealth, but i have always wanted an AIR gap... also have an eddy performer rpm i can pull off my 318.... which intake would be better or would you really notice a difference as they are all dual planes and just cruising with occasional burnouts.. no race...

Click to expand...

I had a Weiand action+ on my set up With varying stages of modifications from deep Port matched runners and contoured Plenum to removal of the divider and at each stage my 60 foot times and ET mile per hour incrementally improved.Then I switched to the Edelbrock airgap and my 60 foot times and everything else improved even further. On my set up with the airgap there was a noticeable seat of the pants Difference. I’d say if you’re not chasing 60 foot times et/mph stick with what you got good is still good

Measure the area of the pushrod pinch area. If the intake runner area is equal or larger leave the intake alone.

Funny, I was marked “Wrong answer” for what you said but thanks for posting your results and the past proven ET slips.

12many said:

I had a Weiand action+ on my set up With varying stages of modifications from deep Port matched runners and contoured Plenum to removal of the divider and at each stage my 60 foot times and ET mile per hour incrementally improved.Then I switched to the Edelbrock airgap and my 60 foot times and everything else improved even further. On my set up with the airgap there was a noticeable seat of the pants Difference. I’d say if you’re not chasing 60 foot times et/mph stick with what you got good is still good

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If you have never been so poor as to have had to install a complete early 318 top-end and cam onto/into a hi-compression 340, then you have missed a very interesting tire-frying combination.
IMO, with 3.55 gears,27" tires,and a 2800TC; the intake port size for a streeter,is a non issue in first gear , and won't be until about after 60mph in second.

With a high-compression 360, you could run a big 2bbl, and a cam at least one size smaller; and on street tires, ET zero to 60 very close to your current combo..... just with a lil less tire-spinning drama, in second gear.
When I swapped out the DC 292 for a Hughes 270, I was a happy happy guy. The 270 traded away ~600 rpm at the top ,which with 3.55s this being after 65mph, was not helping me at all; whereas the newfound torque at sub 2000 (manual trans) was extremely beneficial.

Same goes for the XE 274; it's a great cam! but the power peak in 1.45 second gear with 3.55s, comes at ~5100= 75 mph. At 60 the rpm is ~4000, and most of the power of that cam is on the speeding side of 60mph.
Whereas, the next smaller cam will peak at about 300 rpm sooner.
Ok yeah; the absolute power will be less, but the average second gear power, below 60 mph, could be greater.
It's all about gearing for the application. For the 274 to be effective, you would want the power peak to be at about 300rpm SOONER than the ending speed. So if you are looking at a zero to 60 contest, you would want to gear the car to cross the line at ~5400, and that would require 4.56s for 60=5180, or 4.88s for 60=5540. Like a streeter would ever run 4.56s; YR excluded,lol!
But another ugly thing rears it's head with those deep gears; called tirespin. On the street, with street tires, traction in first gear is nowhere to be found; you will need to spend a buncha buncha money to try and make it hook. So first gear (with 4.56s or more) is a throw away gear, used just to get into second.
But if that's true, then, couldn't you just regear to get the equivalent gearing in first? Why yes you could, But now you are underpowered in first..... so you either need more stall, or a new cam with a lower operating speed, or a bigger engine.
With 4.56s and a 1.45 second gear, your gearing at 60 was 6.61.. You can get that in 2.45 first with 2.69s rounds to 2.76s, and 60=5300 badaboom! But just try taking off with 2.76s and an XE274 cam, in an 8/1 360 .... The 2800TC will help, but you really need more like a 3500, cuz at 2800 the lo-compression 360 is, well, sluggish I think would be fair to say.
To use the 2800TC with 2.76s would take a completely different cam, and more cylinder pressure would be a huge improvement.
Both the 2800 and the 3.55s are a testimony to the lo-compression 360's soft bottom-end with the XE 274 cam.
I have done all these tests over the last 20 years so I'm not just talking math, The math supports the real-world experience.
This is one of the reasons I run the 3.55s, the Commando 4-speed and the GVod/splitter... together with the Hughes 230/237/110 cam at 11:1Scr. It's the mother of all my combos.
Of course not everyone cares about the zero to 60mph speed contest.

Now here comes the point;
>Your combo is NOT set up for zero to sixty anyway; (but rather for 75 mph),
>so I would just slam any old low-rpm dualplain intake on it, with a small 4bbl, and go have fun.
> and now you know the why of it.
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To know where your power peak is; you just need about 5 things;
1) a helper, with
2) a digital stop watch, with at least .01 accuracy; as in 3.06 seconds,as opposed to just 3.
3) a smooth working speedometer, or tach; accuracy not critical
4) a rear seat, and
5) a pencil,paper, graph-paper, and a clipboard
I said about 5,lol.
Install your helper in the back seat with the tools, and head to a deserted road. You will be running thru the power peak in 5mph blocks if using the speed-0 , and your helper will be timing the blocks.
You will need to be in a high enough gear to not have tirespin when you floor it.
If the speeds get excessive, defeat the secondaries.
If the time periods get to be too short to accurately measure, you will need a higher gear or less power, install a throttle stop. The object of this exercise has nothing to do with power, only accuracy.
So in your case I have arbitrarily assigned a powerpeak of 5100 to your combo. I could be wrong and you can prove it.
So, 5100 in first gear is 45 mph, and with a 4bbl you will be whacking thru there way too fast. In second 5100 is 76 mph, and yur gonna run outta road in a hurry, that's if you don't get a speeding ticket..... I ain't paying it.
So whadda you do. I suggest you use first gear but defeat the secondaries and install a throttle stop to limit your primary throttle opening to a repeatable setting, that makes the rate-of-acceleration repeatable, and slow enough to be able to accurately time, and and still allows the rpms to climb to 5800. I use a length of coathanger wire looped over the KD pin and and anchored at the other end in a way that it cannot interfere with the normal operation of the throttle arm and return spring. I install a small wireclamp on it in some way to make the stop adjustable.

Ok the first test is to go out and see if the engine will hit 5800 plus or minus about 100; adjust your throttle-stop until it does and is repeatable.
Now the test can begin.
If you have a tach, you can use it instead of the speedo; it's just as accurate and is probably easier for your helper to read.Choose your first window;I suggest increments of 300rpm until you get the hang of it.
I suggest the first window to be 4600 to 4900. You will begin the test about 200 rpm sooner and end about 100rpm later, but your helper is only gonna record the time from 4600 to 4900.
Next convert this number to seconds per 100 rpm, if it took 4 seconds, then 300/3/4=.750 . if it took 3 seconds then 300/3/3= 1.00, and so on. Write the converted rate of acceleration number down together with the window.
The next window will be from 4700 to 5000, and the next from 4800 to 5100, and so on to end at ~5500.
Your job is to friggen drive the car and not hit anything on the deserted road you chose..
Let your helper run the show, telling you when to hit the gas and when to lift off.
Take your time, this is not a speed contest.

Now, get a piece of graph paper plotting rpm on the horizontal, and rate of acceleration on the vertical. Put your data on the graph,at the center point of the test window and connect the dots. You should get a curve, rising to a peak and then falling; with the fastest rate of acceleration coinciding with the power peak. If you don't have a falling side, repeat the last test adding 100 rpm, same as before.
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You can use this curve to determine your shift points, but with an automatic, you will need an rpm range of at least 2600, ending at ~5800 . Your 727/904 has a .59 split (or 59%) between 2.45 first and 1.45 second. That means if you outshift at 5800 the Rs will drop to .59x5800=3400 so your range is 2600rpm.
But if you outshift at 5200, then the rpm drops to .59x5200=3100, a range of 2100.
That rpm range is called your first gear powerband requirement. Second gear is 69%
So, you will need to start your rate of acceleration at say 3100 less 200, and finish at 5100 plus I think ~700.
To make this test easier and faster, you can stagger the windows to every 500 rpm instead of every 100, because supreme accuracy is not required here, because we are just establishing a baseline. So start at 2500 then 3000, then 3500 and so on to 5500, and again plot the rates in the midpoint of the tests
So as before plot your data and connect the dots. You will get a longer higher line.
To determine your shift points; connect two points on the curve, between about 3400 and 5800, that have very similar rates. This line has to be a 59percenter, meaning that if you choose one point at 5800rpm, the other has to be 59% of that 5800 or 3422, rounds to 3400. If you choose 5400, then the other end has to be at .59x5400=3200.. You may have to go back, and get a finer resolution at the end points.
Whatever line you choose, the big money is on the line being parallel to the base or sloping towards the lower rpm start-point, NOT the other way, altho that way is more fun,lol. It's kindof neat when you outshift second and third gear makes the car jump ahead,lol.

Ok so waaaaay off topic I know, but, that's the AJ-way

OMG!
NOVEL!!!!!!

that's impressive......I had to read it 3 times and im not kidding.....good info aj

When you push play on AJ, stand back!