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Re: MPI Manifold for my 340?
[Re: DropTopE]
#222451
02/14/09 01:38 AM
02/14/09 01:38 AM
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Joined: Jan 2003
Posts: 1,938
Sonora CA
Mopar_Rich
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,938
Sonora CA
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Quote:
I am totally fuel injection illiterate and am hoping someone has done this swap and could walk me through all I need to know & do to convert from the carb to EFI.
Any help / advice / warnings would be helpful at this point.
Thanks,
I wrote a series of 5 short articles for a local Mopar club, that take the easy route to understanding EFI. Go to my web site, then click on Technical downloads, scroll down a little and download the first two articles. They are in Word format and are very short - a few pages each.
They all start with "All you wanted to know about EFI but were afraid to ask ..." There are 5 in total, but the first 2 or 3 will get you there.
www.fastmanefi.com
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Re: MPI Manifold for my 340?
[Re: DropTopE]
#222453
02/15/09 09:37 AM
02/15/09 09:37 AM
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Joined: Feb 2003
Posts: 4,204
Fort Worth, TX
Clair_Davis
master
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master
Joined: Feb 2003
Posts: 4,204
Fort Worth, TX
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FWIW, you CAN modify the Magnum intake to work with an LA, and you don't have to grind down the vertical shoulders to do it. You DO have some grinding to do, but you can do it in a way that you'll end up with an intake that will work on both types of heads:  IMHO, if you haven't already got a good set of heads (or domed pistons), you may want to take this opportunity to upgrade to some Magnum-style heads. That'll give you a bump in compression, better ports, and no need to modify the manifold... Clair
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Re: MPI Manifold for my 340?
[Re: Clair_Davis]
#222454
02/15/09 11:53 AM
02/15/09 11:53 AM
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Joined: Sep 2005
Posts: 401
Berlin, Germany
Flo
mopar
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mopar
Joined: Sep 2005
Posts: 401
Berlin, Germany
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I would like to jump in here if that is OK and add my question.
It seems like I have a somewhat similar setup: 344 with ported 302s with 2.02 valves. At the moment I have an Eddy Performer and a 600 carb. Still dialing it in on the dyno... I will have that motor on the dyno for the next two to three months and a lot of time to play around with it and work out the bugs.
I already have a distributorless ignition and want to go Megasquirt next. This motor must have some lowend-torque as it will go in my 67 Fury. Stripper car (no options except AC), nevertheless not superlight. Cam is Comp 264HR with 1.6 roller rockers, I may be Ok with going one step hotter. A500-trans (low first) with 3.23 gears (cannot go deeper... Germany... Autobahn...).
The only EFI-manifold I see is the Edelbrock 28155. This is a Super Victor thing, which seems totally off for my motor. I do not want too loose of a converter in my mainly street driven car, so I would like torque starting somewhat at 1500rpm latest. My stock hydraulic roller lifters will be done at 6000rpm, if there is a useful option I would upgrade, but it stays hydraulic roller. Is there a manifold out there with injector bungs for my application?
If it was carbed I would think the air gap is the way to go from what I read. Is converting an airgap to EFI a good idea?
Anyone having some real world experience?
Thanks
Flo
PS: reading Rich' articles... and his cookie recipe :-) hmmmm.... :-)
Last edited by Flo; 02/15/09 04:18 PM.
1967 Fury III 4door HT
tiny 318, late model roller block, bored and stroked to 344
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Re: MPI Manifold for my 340?
[Re: Flo]
#222455
02/15/09 12:52 PM
02/15/09 12:52 PM
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Joined: Jan 2003
Posts: 1,938
Sonora CA
Mopar_Rich
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,938
Sonora CA
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Quote:
I would like to jump in here if that is OK and add my question.
Is converting an airgap to EFI a good idea?
Anyone having some real world experience?
Thanks
Flo
PS: reading Rich' articles... and his cookie recipe :-) hmmmm.... :-)
Flo.
I have converted several air-gap manifolds to port injected EFI. They work great. I'll round up a few pictures. Remember, with port injected EFI the manifold stays dry so almost any manifold can be used if you're willing to do the machine work and the welding.
Let me know what you think about that cookie recipe. They are a crispy cookie, so you have to be okay with that, but most people like them.
BTW: There's nothing wrong with using a single plane intake with EFI. When you are injecting at the port you can use almost any manifold you like. The low RPM characteristics of a single plane are not the same with EFI. I've done many single plane manifold on low stall street car with good success.
Good luck
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Re: MPI Manifold for my 340?
[Re: Flo]
#222456
02/15/09 01:07 PM
02/15/09 01:07 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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I have a very similar setup to what you are talking about, except it has a couple of turbos on it besides. My 302 heads have the 1.88 intakes, as the 2.02's don't really gain much with the flow available in the ports, and cost you a bit of velocity. I am much milder on cam with a 208/201 @ .050, and 1.5 adjustable rockers. My pistons are matched in shape to the quench pads on the heads and then dished at 8.25 to 1. Quench is at .038. Your desire for good torque starting at 1500 may be tough with the combo you have, especially if you go with a big manifold. Even a Perf RPM may be a bit big, and it has the big ports comapared to the 302 heads. I am running a regular Performer on mine, and it matches the rest of the setup very well. I get excellent torque at 1500 at it will pull past 5500. I would stay away from any of the big single planes, even for efi. The better balanced flow from a good dual plane will work much better for efi (I know others will disagree with this). A regular Perfomer should be able to get you near 400hp without a problem. I am running a FAST bank to bank system with vacuum/boost referenced fuel pressure. Here is a pic of the Performer. I did angled injectors on it to try it out. Probably not work the extra work, and many manifolds don't have room anyway. This was before the adjustable rockers were put on. 
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Re: MPI Manifold for my 340?
[Re: Mopar_Rich]
#222458
02/15/09 04:26 PM
02/15/09 04:26 PM
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Joined: Sep 2005
Posts: 401
Berlin, Germany
Flo
mopar
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mopar
Joined: Sep 2005
Posts: 401
Berlin, Germany
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I thought that single or dual plane should not really matter with port EFI. But as I said (and others seem to agree) the Victors seems to have way too large runners. Would a smaller single plane be the best bet? Like Torker intake?
I think the Megsquirt is not far enough to do real sequential injection. I would have to add a cam sensor anyway, running wasted spark with an EDIS-system at the moment. (runs pretty good by the way).
I would be very interested in getting a converted manifold from Rich. I CAN do the fab and welding... but if you already have all the jigs and the experience to get the angles right... there will be plenty of work left for me! NOt sure what is the best manifold yet.
Depending on how long that motor stays on the dyno I may think about forced induction too... 9.5 c/r might be a little high though.
1967 Fury III 4door HT
tiny 318, late model roller block, bored and stroked to 344
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Re: MPI Manifold for my 340?
[Re: Flo]
#222459
02/15/09 04:52 PM
02/15/09 04:52 PM
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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I know booster likes his dual plane intake for port efi. Looking at the ports, their shape and size, I'm not a huge believer in the use of dual plane intakes for efi, but he says his real world results show they work. I picked up a port efi victor for my big block. I'll give it a try, if it doesn't perform well I can always swap it out for something else later on. Quote:
I think the Megsquirt is not far enough to do real sequential injection.
Uhh, the megasquirt designers are beta testing the MS-2 Sequencer, megasquirt's sequential fuel injection controller. Probably just a matter of months before that unit hits the market...
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Re: MPI Manifold for my 340?
[Re: Flo]
#222460
02/15/09 05:18 PM
02/15/09 05:18 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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You might want to do a search on the dual or single plane for efi as it has been discussed here many times.
The issue is not really dual or single plane as it applies to a carb setup. There the dual plane splits the pulses to give better signal to the carb, and obviously that doesn't apply to efi.
For efi, I like a dual plane because you can get them with much better matching runner lengths. To me that is one of the MOST important characteristics, if you are going to be making a steet car that sees a wide rpm range.
The arguement that is given for it not making a difference is usually that the injectors all give the same amount of fuel to each cylinder, so it has to be the right mixture. That would be true, except that the cylinders get different amounts of AIR, if the runners don't match. You actually get worse mixture matching, cylinder to cylinder, than you would with the same manifold and carb.
The next arguement is that if you run sequential with individual cylinder fuel trimming, you can tune out the mismatch. This is true, but only for one rpm range, as the trim puts the same percent change on the whole rpm range. If you take a look at the flow of a manifold with mismatched runners, you will find the mismatch in flow will be way different at 1500 rpm than at 5500. The reason is very easy to understand. At a particular airflow, you can have a short, small runner flow the same as a long, big runner, but at a different airflow the runners react differently to the change, and then they flow differently. It is essentially impossible to get a manifold with non-identical runners flow evenly over a wide rpm range.
I have tested quite a few manifolds, mostly dual plane, but also singles. I don't have the option of individual cylinder egt or mixture reading so I used plug reading to test. What I did was setup and run at low cruise 1500 rpm for an hour and stop and read the plugs. Then the same highway cruise 2500 rpm. Then the same after several full throttle full rpm runs. Once I compiled the data, it was extremely obvious that the closer the runners matched, the more even the plugs looked, cylinder to cylinder, over the whole rpm range.
Interestingly, the worst manifold I tested was a dual plane, the Weiand 8007. If you look at it, you can see why. It has the longest runners something like 5 times longer than the shortest. The best for match was the M1 dual plane, that is very similar design to the old cast 340 manifold. The runners tee and then go equally to their cylinders. Right behind it was the regular Performer. The best single plane was the Street Dominator, which performed very well power wise, but the mismatch limited mileage at cruise because the mixture mismatch caused lean miss. The best to worst manifold showed about 10% difference in fuel economy. The best manifolds would go 40K on plugs (cold ones because of the turbos), where the worst would foul some of the plugs in under 1K.
If you look at all factory efi intakes, you will see they are fanatical about matching runners. This is one of the reasons they can get such a wide, flat torque curve, long plug life, and good economy. They wouldn't do it if it wasn't important.
I will try to scare up some manifold pics that show the runner lengths. It is pretty interesting stuff.
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Re: MPI Manifold for my 340?
[Re: DaytonaTurbo]
#222461
02/15/09 05:21 PM
02/15/09 05:21 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Daytona, I just recently finished a Torker and a RPM for a 383 a friend is putting together. NA for now, turbos later. Hopefully, he will be able to do some testing of them and give some feedback.
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Re: MPI Manifold for my 340?
#222462
02/15/09 05:36 PM
02/15/09 05:36 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Here is the Weiand 8007. Look at the length of the runner to cylinder 5 compared to cylinder 8.  Here is the M1 dual plane. Note how the runners head to the center of the manifold and then tee back to the cylinders to keep them even.  Here is a regular Performer. The teeing is less obvious, but when you measure the runner length they are very close to the same.  Here is Performer RPM. Also pretty well matched.  This is a Viper manifold. Very typical of the modern intake designs.  Daytona, this is the Torker I did. 
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Re: MPI Manifold for my 340?
[Re: DaytonaTurbo]
#222464
02/15/09 06:12 PM
02/15/09 06:12 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Daytona-There absolutely are better and worse within each catagory, look at the 8007 above, but from what I have seen in my testing, the runner match is, far and away, the best predictor of flow balance over a wide rpm range. What dual plane with equal runners have you seen that has bad airflow matching? I would love to see it and try to find out why.
I don't say that it is a single or dual plane issue. What I say is that you can't find a single plane with runners that match very well in street rpm ranges, but you can find well matched dual planes. If you could get a single with matched runners, it would be fine. A lot of the factory efi manifolds are single plane by definition.
One thing that you have to remember is that I am testing with efi. In particular, a single plane could give horrible distribution on a carb, but much better on efi, because single planes are famous for bad distribution because of carb signal and cylinder robbing. The Torker in the picture above will probably be fairly well balance setup, based on the runners, but it is way big for most street applications. You will give up an awful lot of bottom with it. I did not test anything anywhere near that big as I am in the lower rpm ranges on my engine.
So what I am saying is that you can't go by how the distribution is with a carb and apply it to efi. Besides the carb signal issues, you also have wet/dry flow to consider, but as with any flow, if the runners are the same, they will flow the same. Also remember that matched runners not only should match length, but they should be the same crossection and shape, with similar turns. The further you get away from a manifold like the Viper one shown, the worse your mismatch of flow over rpm range is going to be.
To accurately evaluate the individual manifolds for efi, you have to actually test them with efi and keeping other things equal. You can't go by anything learned with a carb.
I would love to see complete testing of any manifolds to see how they did, if anyone has them.
If you are stickler for definition accuracy, the "dual planes" that I use are not really dual planes as I always totally remove the divider, which is there to improve carb signal and only hurts me.
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Re: MPI Manifold for my 340?
#222465
02/15/09 06:41 PM
02/15/09 06:41 PM
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Joined: Jan 2003
Posts: 1,938
Sonora CA
Mopar_Rich
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,938
Sonora CA
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Quote:
The arguement that is given for it not making a difference is usually that the injectors all give the same amount of fuel to each cylinder, so it has to be the right mixture. That would be true, except that the cylinders get different amounts of AIR, if the runners don't match. You actually get worse mixture matching, cylinder to cylinder, than you would with the same manifold and carb.
Booster-
I take issue with this statement because once you go sequential injection you can control EACH Cylinder's fuel (and timing) independently. Yes - on the dyno with a poorly designed dual plane you can see quite a variation in EGTs and A/F ratios; but once you start tuning each cylinder that all goes away. I've done it many times.
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Re: MPI Manifold for my 340?
[Re: Mopar_Rich]
#222466
02/15/09 06:45 PM
02/15/09 06:45 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Rich, you will notice in the next paragraph I addressed the individual cylinder tuning. Unless you can do it to do a different % at different rpm for each cylinder, you can't correct for a bad manifold, because the mismatch changes with rpm.
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Re: MPI Manifold for my 340?
[Re: Mopar_Rich]
#222468
02/15/09 09:46 PM
02/15/09 09:46 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Are you doing the sweep over the full rpm (idle to redline) range? I assume at WOT. How about part throttle conditions? To simulate cruise you would have to be pulling only 10-20 horsepower on the dyno, I would think.
Is the 5% for AF or EGT, or both? Plus and minus or total high to low?
I find the numbers to be interesting and can give some insight into what I have found, % wise.
When I was running the last engine (bigger open chamber heads, more cam) the difference I would see in the onset of lean miss at cruise with different manifolds would be about 1/2 point of AF. It was right in the range of 14.4 to 13.9 which is within 5%. I would have to richen up everything to get the leanest cylinder to quit missing. Unfortunatel, I don't know what the actual mismatch was. From reading the plugs, I could tell which cylinders were going lean, as there was enough difference to show on the plugs. I did a bunch of testing by balancing the flow to get even distribution (epoxy and popsicle stick style) and could get a bad manifold to have even distribution and run at the .5 AF higher, but when I did the other tests at different rpm and load, it would be off again. The good manifolds didn't exibit a change between the tests and ran well at the high end of 14.4 AF at cruise and 12.5 under boost. With the worst of the manifolds, I would have to turn on the water injection 2 psi sooner to prevent detonation at 12.5 AF. If I took it to 12.0 I got the 2 psi back. The good manifolds were OK at 12.5.
The current engine on the 302 heads, Performer, lots of quench is extremely resistent to detonation and lean miss, and I think the higher velocity in the runners also helps. I will go down the highway at 60 mph, 2100 rpm, manual trans at up to 17 AF. Granted, the throttle is a bit soft at that setting, but it doesn't miss. It also doesn't show a change in egt compared to running 15, so I appear to get full burn at both settings. Fuel consumption is essentially identical also. Under boost, this engine will go at least 2 psi higher than the old engine without detonation, even though the compression is higher.
I understand that my goal of very good efficiency and lots of brute force are different than most of the coversions done. The turbos allow me to run a combination capable of much higher efficiency, and leaner mixtures than most hipo engines. If a person is dealing with an engine that has a bunch of cam, big heads, set up to go 6500+ rpm, etc, and on an automatic, it is not going to run really lean anyway, so if you have .7 AF (5% difference) between cylinders, you probably wouldn't even feel it, or see it on the plugs.
Your tuning at the torqe peak is a good one, as it is near the middle of the useful WOT rpm and also where you are likely to do damage from mixture issues. It also makes sense that you would see error there, as the combo has a natural sweat spot based on cam, heads, and intake design. If a runner is different than the others, it will have a different sweet spot and underperform compared to majority.
Just one more question. Have you ever run that same sweep on a matched runner OEM engine to see how well they match? That would be very interesting information!
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Re: MPI Manifold for my 340?
#222469
02/16/09 12:21 AM
02/16/09 12:21 AM
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Joined: Jan 2003
Posts: 1,938
Sonora CA
Mopar_Rich
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,938
Sonora CA
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Quote:
Are you doing the sweep over the full rpm (idle to redline) range? I assume at WOT. How about part throttle conditions? To simulate cruise you would have to be pulling only 10-20 horsepower on the dyno, I would think.
I run from idle to a safe RPM usually just past torque peak. I do it by having the dyno hold the RPM (500 RPM increments) and sweep the throttle from idle to WOT (if the dyno can hold it). That way I pretty much cover the entire "safe" range, NOT just WOT.
Quote:
I would have to richen up everything to get the leanest cylinder to quit missing. Unfortunatel, I don't know what the actual mismatch was. From reading the plugs, I could tell which cylinders were going lean, as there was enough difference to show on the plugs.
I would first use the EGT as an indicator. But after adjusting EGTs, by adjusting individual cylinder fuel, I switch to cylinder timing adjustments. Advancing the timing leans out a cylinder to a much finer precision than changing the injector pulse width - and I'm able to do timing changes as a function of RPM which I cannot do with the fuel.
Maybe I'm not a good plug reader but at this point I'm not able to see changes by reading the plugs.
I have only done this with normally aspirated engines, never forced induction.
Quote:
Your tuning at the torqe peak is a good one, as it is near the middle of the useful WOT rpm and also where you are likely to do damage from mixture issues. It also makes sense that you would see error there, as the combo has a natural sweat spot based on cam, heads, and intake design. If a runner is different than the others, it will have a different sweet spot and underperform compared to majority.
That is exactly what I have found out to be true.
Quote:
Just one more question. Have you ever run that same sweep on a matched runner OEM engine to see how well they match? That would be very interesting information!
Sort of. I've done this testing using dual-plane stock type manifolds to pro-stock sheet metal manifolds. The last sheet metal manifold I looked at needed no adjustments at all - but virtually every other manifold could have been improved if I was willing to spend the time doing the tuning.
You Also asked:
Quote:
Is the 5% for AF or EGT, or both? Plus and minus or total high to low?
Good question! I guess it depends. I felt if I could get +/- .03 A/F ratio with less than 5 degrees of timing adjustments I was happy. But sometimes I could never get there. I also could never predict what the engines ideal A/F ratio would be at a particular load/RPM/vacuum point. So once (sorry I only did this once} - I first zeroed out the map as best I could. Then I data logged the TORQUE at all the test points - about 5 for each 500 RPM increase. Then I went back to each point statically, and changed both the overall A/F (via VE) and ignition timing looking for maximum torque. What I found out - Engines like to run lean as long as they don't misfire or ping. DUH! I quit for the day and went out and had a beer.
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Re: MPI Manifold for my 340?
[Re: Flo]
#222470
02/16/09 09:50 AM
02/16/09 09:50 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
I would like to jump in here if that is OK and add my question.
It seems like I have a somewhat similar setup: 344 with ported 302s with 2.02 valves. At the moment I have an Eddy Performer and a 600 carb. Still dialing it in on the dyno... I will have that motor on the dyno for the next two to three months and a lot of time to play around with it and work out the bugs.
I already have a distributorless ignition and want to go Megasquirt next. This motor must have some lowend-torque as it will go in my 67 Fury. Stripper car (no options except AC), nevertheless not superlight. Cam is Comp 264HR with 1.6 roller rockers, I may be Ok with going one step hotter. A500-trans (low first) with 3.23 gears (cannot go deeper... Germany... Autobahn...).
The only EFI-manifold I see is the Edelbrock 28155. This is a Super Victor thing, which seems totally off for my motor. I do not want too loose of a converter in my mainly street driven car, so I would like torque starting somewhat at 1500rpm latest. My stock hydraulic roller lifters will be done at 6000rpm, if there is a useful option I would upgrade, but it stays hydraulic roller. Is there a manifold out there with injector bungs for my application?
If it was carbed I would think the air gap is the way to go from what I read. Is converting an airgap to EFI a good idea?
Anyone having some real world experience?
Thanks
Flo
PS: reading Rich' articles... and his cookie recipe :-) hmmmm.... :-)
flo- if you're looking to maximize idle-5000 RPM performance and torque, you might want to think about swapping over to a magnum style head and running a stock magnum intake (the "beer barrel"). they're a very long runner manifold and are awesome torque producers.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: MPI Manifold for my 340?
[Re: patrick]
#222471
02/16/09 11:02 AM
02/16/09 11:02 AM
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Joined: Sep 2005
Posts: 401
Berlin, Germany
Flo
mopar
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mopar
Joined: Sep 2005
Posts: 401
Berlin, Germany
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well, changing heads is out of question for now. Spent some effort and money in the 302s.
But one of these stock intakes might be interesting to try for comparison as I expect them to be fairly cheap.
Last edited by Flo; 02/16/09 11:29 AM.
1967 Fury III 4door HT
tiny 318, late model roller block, bored and stroked to 344
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Re: MPI Manifold for my 340?
[Re: Rug_Trucker]
#222473
02/16/09 12:06 PM
02/16/09 12:06 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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"I would first use the EGT as an indicator. But after adjusting EGTs, by adjusting individual cylinder fuel, I switch to cylinder timing adjustments. Advancing the timing leans out a cylinder to a much finer precision than changing the injector pulse width - and I'm able to do timing changes as a function of RPM which I cannot do with the fuel."
Rich,
I am having some problem understanding how this works. How does advancing the timing make it go leaner. What happens to egt when you do it?
Are you reading your AF with O2 sensors, or do you have gas analyzer also?
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Re: MPI Manifold for my 340?
[Re: Clair_Davis]
#222474
02/16/09 01:57 PM
02/16/09 01:57 PM
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Joined: Mar 2005
Posts: 168
Central New York
DropTopE
OP
member
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OP
member
Joined: Mar 2005
Posts: 168
Central New York
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Quote:
FWIW, you CAN modify the Magnum intake to work with an LA, and you don't have to grind down the vertical shoulders to do it. You DO have some grinding to do, but you can do it in a way that you'll end up with an intake that will work on both types of heads:
IMHO, if you haven't already got a good set of heads (or domed pistons), you may want to take this opportunity to upgrade to some Magnum-style heads. That'll give you a bump in compression, better ports, and no need to modify the manifold...
Clair
WOW - my thread really got some great technical action over the weekend. I have been trying to absorb all the differences and understand the impact to my situation. Thanks for all the input on this guys !
I will likely use the Magnum manfiold that is modified to work with LA heads. My present set up is the small chamber version aluminum edelbrock head with stage 3 porting so I will be retaining the LA heads. I have tons to learn about here and most of my questions are so far down on the learning curve they are not being hit in this thread. I have made some initial contact with Rich and will be following up with him on this quickly.
Thanks again !
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Re: MPI Manifold for my 340?
[Re: DropTopE]
#222475
02/23/09 12:09 PM
02/23/09 12:09 PM
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Joined: Sep 2005
Posts: 401
Berlin, Germany
Flo
mopar
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mopar
Joined: Sep 2005
Posts: 401
Berlin, Germany
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well, I am still not sure what manifolds to buy/try.
I totally agree with the idea of even air distribution. But actually a properly done single plane should be better in achieving this than a dual plane!
I will have some dyno time so I like to try several of these manifolds, but I do not want to sink endless money in buying manifolds I dont need.
-I think I will definitely get an Air gap or the knock off version.
-I already have a regular performer.
-I am considering getting an old Edel Streetmaster. Actually the idea of a small single plane makes sense to me. They are cheap on Ebay and I am curious how they do.
-Also I would like to try a modern single plane. There are so many MP part nos out there and I cannot find a good explanation for them:
P4876334
P5249614
P5007380
P4876334
Anyone tested any of these and has some results.
-There is still the Torker II, is that thing too large for a street motor which is done at 6000rpm? Anyone tried one with EFI?
Regards
Florian
1967 Fury III 4door HT
tiny 318, late model roller block, bored and stroked to 344
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But what I do, is I sweep the RPM range, data logging the mismatch. Then I zero out the worst RPM/load point. Then I make a few pulls to see how far out the rest of the map is. It's usually within 5% because the largest mismatch is usually close to torque peak. If it's within 5% I call it a day. 
