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Just received my 331 back from the engine builder including having him put an original Ford C9OX intake on that I had for 35 plus years. Then tonight on a video my neighbor sent me showing dyno testing using carburetor vs Holley Sniper. Dual plane intake with the carb and the engine ran fine. They put the Sniper on the same intake and had a bad time getting it to run. They then switched in a single plane intake and the Sniper ran perfectly. What are you guys with the Sniper's using for intakes and the brands?
 

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WunderW, the Holley Sniper has its MAP sensor located badly, it is a poorly thought out product. The Holley guys screwed up big time, placing the Manifold Absolute Pressure sender way off to one side. Choose another setup and look for one that works on a dual plane. Even if you choose to run a asingle plane, if the manufacturer doesn't know how to locate a MAP sensor, what else have they screwed up ? LSG
 

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If you are talking about the video on the link below it is complete BS and it wasn't a Sniper. Sometimes it takes more tuning than these guys had time for. I know they are Engine Masters, therefore, they must know everything. They spent a whole morning trying to tune it. Listen carefully to what the older guy who always knows everything says at 7:45 in the video: "I don't know." That was in 2015. Somehow that misinformation just won't die.
 

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Tb injection works better with single plane intakes. You wont lose torque or drivability with the tb because the injection system isn't relying on the vacuum signal to deliver the fuel.
 

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Red, you're mistaken. The TBI systems do rely on vacuum. The MAP sensor tells the ECM what is happening in the intake, and the ECM then uses that information to choose how much fuel to spray. Ford, GM and Chrysler have all built hundreds of thousands of automobiles with TBI and dual plane intakes, they work fine. Unfortunately however, there are some aftermarket TBI systems out there that are not nearly as well engineered. The OEMS can apply far more engineering and money to figure these things out. Some of the aftermarkets have badly missed the mark by installing a MAP sensor on the side, so it doesn't get a good signal. Its not that TBI prefers single, its that SOME of the aftermarket systems are poorly designed. LSG
 

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Red, you're mistaken. The TBI systems do rely on vacuum. The MAP sensor tells the ECM what is happening in the intake, and the ECM then uses that information to choose how much fuel to spray. Ford, GM and Chrysler have all built hundreds of thousands of automobiles with TBI and dual plane intakes, they work fine. Unfortunately however, there are some aftermarket TBI systems out there that are not nearly as well engineered. The OEMS can apply far more engineering and money to figure these things out. Some of the aftermarkets have badly missed the mark by installing a MAP sensor on the side, so it doesn't get a good signal. Its not that TBI prefers single, its that SOME of the aftermarket systems are poorly designed. LSG
lol, the fuel is still not delivered by vacuum as it is in a carb set up. The injectors are still delivering the fuel.
 

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EFI systems work better with single plane intake.

I have a different manucturer's EFI (mass-floefi) and talked to them about the difference thinking a dual-plane would provider better low end torque. Had a long discussion with him about the engineering reasons why you want single plane...I don't remember all the details but it did boil down to EFI working better with a larger air plenum.
 

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DB, either your engineer doesn't know what he is talking about, or you misunderstood him, or, most likely, he is refering to the type of TBI that his company sells. Many aftermarket setups have the port for the MAP way off to one side. In the Rochester 2bbl TBI that many are familiar with, the MAP sensor is usually out of the way and connected to the TBI with a long hose. If you look at the underside of the Rochester, there is a port in the center that is in the middle of the casting and has a channel that lets the MAP see the vacuum from both sides. Works very well. Unfortunately, in their zeal to make things easy for the car's owner, lots of the aftermarket systems have the MAP sensor built into the unit, and it is usually off to one side. It is just a sloppy design. And, because most carburated street cars alredy have a dual plane, these guys are reducing the market for their own product.

If you think you want a throttle body injector system, you would do well to study the Rochester 2bbl TBI. GM built more V8 throttle bodies than all of the others combined. The driveability is very good, and the design is durable and well understood. And they were all on dual plane intakes. Even if you choose some other brand of TBI, if you learn about the Rochester, you'll be better able to figure out how your system works and why it does what it does.

LSG
 

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I'm running a Holley Sniper system on a roller cam 302. The engine had a "standard" Edelbrock Performer 289 intake (dual plane) and I had read lots of threads about how single plane is better. When I did the original install of the sniper, and since the performer 289 is a very low-rise design, I ran a 1" open spacer between the intake and the Sniper TB. The car ran fine. I had other issues (timing related to the 2 wire MSD ignition primarily) but the open spacer certainly solved any possible "wall" issue of a dual plane. Anyway, I had an oil leak on the back side of the 289 intake, and I was frustrated with the MSD set-up, so I ripped off the intake and installed an Edelbrock RPM Air Gap intake and a Hyperspark distributor. The Air gap dual plane "wall" is milled down about a half-inch in the center (the standard RPM is not) and I am running Sniper without a spacer with this intake. About 10 miles on it so far and runs great. Lots of people are running the air gap with TB EFI with good success. I'd recommend it for a street performance engine (I have Edelbrock RPM aluminum heads and camshaft, roller rockers, exhaust, etc) where you want it to pull well to low 6000s and still pull cleanly at 1500 RPM as well. You can also try a spacer if your hood clearance is OK. There are also a lot of people running Torker II or similar intakes and seem to like them. I was concerned about a 3500 - 8000 RPM spec intake so I went air gap and am pleased. Good luck!
 

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450hp roller 331 in my '65. I've tried Performer RPM(not the 289), Torker II, Vic Jr. S2MS shelby and now RPM air Gap.

ZERO difference in drivability between single and dual plane. The single planes however KILLED low and mid range on the car. The Air Gap made the most power of the dual planes (and better than the Toker II)... The Vic Jr. made the most peak power.. but huge drop in torque and power below 4800rpm and I couldn't run my stock hood. So.. Its got the RPM air gap on it and we port matched it to the PW ported heads.

I really did not care much for the Torker II and would only use it if hood clearance was an issue for you.. but the air gap fits nicely under my hood with a hipo air cleaner.
 

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Zero point running a dual plane with EFI because you will not really get the dual plane effect. Any advice to the contrary pertaining to TBI systems from 1983 is absurd. Pay it no mind.
 

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Disagree. I don’t want to give up low and midrange at the sake of peak power.
 

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I'm gonna run pro flo 4, it comes with a single plane intake...
 

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450hp roller 331 in my '65. I've tried Performer RPM(not the 289), Torker II, Vic Jr. S2MS shelby and now RPM air Gap.

ZERO difference in drivability between single and dual plane. The single planes however KILLED low and mid range on the car. The Air Gap made the most power of the dual planes (and better than the Toker II)... The Vic Jr. made the most peak power.. but huge drop in torque and power below 4800rpm and I couldn't run my stock hood. So.. Its got the RPM air gap on it and we port matched it to the PW ported heads.

I really did not care much for the Torker II and would only use it if hood clearance was an issue for you.. but the air gap fits nicely under my hood with a hipo air cleaner.
You don't happen to have the Dyno run numbers/graphs do you ? I'm just curious exactly how much a "huge drop" is ?
 

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Jdub, I believe you're mistaken. The dual planes are almost ALWAYS a better choice for a street driven can, and alot of the drag cars as well. It shifts the power curve around. I will gladly give up 15hp at 6500 rpm to gain 20 lbs-ft of torque at 4K. I spent alot more time between 2500~6000 than I do above 6500. And Ford started TBI in 1984, and Chevy in 1987 through 1995. Its a decent system, if you know how to program it, and have a VRFPR that is adjustable. LSG
 

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Jdub, I believe you're mistaken. The dual planes are almost ALWAYS a better choice for a street driven can, and alot of the drag cars as well. It shifts the power curve around. I will gladly give up 15hp at 6500 rpm to gain 20 lbs-ft of torque at 4K. I spent alot more time between 2500~6000 than I do above 6500. And Ford started TBI in 1984, and Chevy in 1987 through 1995. Its a decent system, if you know how to program it, and have a VRFPR that is adjustable. LSG
I am not mistaken. The dual plane effect doesn't work that well without a carb. A carb uses vacuum directly to meter fuel. These aftermarket systems use Speed Density to meter fuel. The computer knows manifold pressure, intake air temperature and, importantly, RPM. A carb doesn't know any of that, it only knows the vacuum it is seeing. The dual plane effect relies on a specific set of conditions to be effective, one of those being fuel metered by vacuum. To make it work with fuel injection you'd need two MAP sensors, one for each set of runners. I've tried to explain this to you before, you simply did not want to try to understand. Run a dual plane with fuel injection, I don't care, but it won't be doing much for you.

For those who are interested in understanding the facts, if you want fuel injection but don't want to change manifolds, you should run an open spacer.
 

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You don't happen to have the Dyno run numbers/graphs do you ? I'm just curious exactly how much a "huge drop" is ?

I don't have the printouts but I was watching the screens while it was in the dyno cell. 20lb/ft tq difference between the Torker and the air gap. The Vic Jr was about 18lb/ft less.. although it made +9hp more from 6000- 6700rpm where we stopped.

I do have the print out from the final run with the port matched Air Gap...
 

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Jdub, I am going to persist in the idea that TBI will improve if well thought out on a dual plane. I don't recall you or anyone else being able to explain why not. What you are calling a 'dual plane effect' is not just the vacuum pulling on the carb, it is the size, shape, layout and separation of runners that makes the difference. If a carb is replaced by a TBI, the entire manifold is still wet, and fuel mixture will travel the same way as with a carb. The problem in single planes is that ajacent cylinders can steal some of the charge from each other because the runners aren't separated enough. The cylinders in a dual plane all have 180* of rotation separation from each other, carb or fuel injection won't change that. If you have some explanation of how a single plane TBI can overcome its design limitations, I want to hear it. I still think you're mistaken. Explain ! Discuss ! Defend your viewpoint ! If you think the dual planers are incorrect, educate us. Allow us to explain why we think what we think, and if you HAVE misunderstood something, you can learn from us.

LSG
 
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