Worth Swapping Intakes??

[MKSpeedlab]

So since parts are sometimes hard to come by right now with everything going on, Im likely going to wait till the fall/winter to swap the heads/cam/headers and all the goodies I have to go on. But I am curious if it would be worth putting the Torker intake I have on in place of the Performer thats on there right now. Everything is mostly stock 351C for now besides a lower stall converter(1500), and the Holley Sniper EFI. I have heard the EFI set ups prefer single plane, but just not sure if its worth me putting on the Torker, or if I should just run it the way it is for the season. 

 

[Galucha]

I've heard a lot of opinions on how much power you're missing out on by using a dual plane vs a single plane intake for EFI. The consensus is usually that the single plane is better suited in general for EFI, but I've never seen a direct comparison that shows just how big the power difference is.

I've heard the biggest issue issue with running a dual plane with Holley EFI is not actually the runner design, but the intake plenum divider. With a plenum divider like the one of the Performer intake, the MAP sensor is only measuring from one bank of the engine, which will ultimately cause issues with the EFI computer finding a good tune. Look at it this way, a carburetor is able to meter independently on each side via the venturi effect. If one bank of cylinders is pulling even slightly more vacuum than the other side, fuel is pulled out of the venturis to meet the demand. Throttle body EFI relies on (among other things) the MAP sensor to gauge how much air/fuel the engine needs, which is why having an open plenum is important, since the air/fuel demand is more equalized.

Having said that, I don't think its hurting anything to leave the dual plane on there if its running fine, but you could potentially see more horsepower by adding an open spacer until you swap on the Torker.

 

[MKSpeedlab]

I guess i should mention I do have a 1" open spacer on there right now. Forgot all about it till you mentioned it. 

 

[c9zx]

I don't think the Torquer would work well with the 1500 RPM stall convertor and, if I remember correctly, a 3.00:1 rear gear. The loss of low RPM torque would be very noticeable I believe. Unless you plan to rev it past 6500 RPM I see no need for a single plane intake. I really have to question the more power with single plane using a sniper unless the RPMs are high. Aftermarket EFI seems to be a radically updated version of the GM TBI that was coupled to dual plane intakes for about 15 years. Chuck

 

[Lazarus]

I had a torker intake on a very strong 406 small block in a Camaro.  It made good high-end power but was not great on the low end. It definitely needed more than a 1500RPM stall converter.  Probably twice that. Obviously my cam also was pretty lopey but it was supposed to be a good match for the intake.

I can sorta buy that the EFI could have a better feedback loop from the single plane intake but I think the flow of the torker in particular may not be the best single plane.  I loved my setup but it was a tad aggressive for the street. 

 

[Tnfastbk]

I run a Edelbrock Airgap with my MSD Atomic set up with zero issues. When it was carbureted I had a single plane intake and a 750DP carb. Ran great at wide open throttle. But how often do you really drive wide open. Did I lose a little top end? MAYBE? The dual plane made it a lot easier to drive in traffic and picked up a ton on the low end.  But each engine is different and like different things. Good luck.

 

[tony-muscle]

I have dual plane Blue Thunder with a FiTech EFI and no issues. I later added a 1/4" open spacer to see if it made a difference when "opening" up both plenums, but there was not noticeable difference (1/4" is as much as I can fit under the RAM Air hood). Maybe there would be dyno difference but not enough to be noticed while driving.

 

[Don C]

The Shelby (Blue Thunder) intake has a fairly significant slot in the plenum divider that equalizes both planes of the plenum and should provide enough equalization to work with a Sniper. 

 

[tony-muscle]

The Shelby (Blue Thunder) intake has a fairly significant slot in the plenum divider that equalizes both planes of the plenum and should provide enough equalization to work with a Sniper. 

View attachment 50050

That's correct. Please let me know where I can buy at that price so I can buy a dozen....

 

[droptop73]

There is a difference in port EFI and a throttle body EFI. Since the port EFI uses a dry manifold and throttle body the single plane works great due to its increased volume of air moved. Typically it's hard to oversize a dry throttle body and manifold. The dual plane will work better with a wet throttle body EFI like the Sniper due to increased flow velocity. The wet throttle body EFI characteristics are much closer to a carburetor than a port EFI. 

 

[Carolina_Mountain_Mustangs]

I wish some rich guy would go buy every intake, every head, every cam, every fuel system, every piston and do about a years worth of dyno work to answer all the questions. We are all just guessing. My two cents. A single plane is not meant for the street. Are you building your car for 1% of your driving?

 

[Don C]

That's correct. Please let me know where I can buy at that price so I can buy a dozen....

Wouldn't that be nice  :biggrin:

Did you read what Shelby had to say about carburetor size? I know that 351Cs like a lot of fuel and air, but I never considered one that big.