CSA in dual planes ?

[Tom68]

Is there any sort of listing ?

I know the lower runners in low dual planes are very small, so I guess really they should only be used on tiny heads even though they can perform quite well.

If we're striving for tapered runners and even a 1971 C3BX ports fit a 1205, what manifolds are bigger than a 1205 upstream ?

I like the old Weiands and Edelbrocks, whilst they were low, they traded height for width upstream.

C3BX.jpg

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[F-BIRD'88]

I could be wrong on this but I believe the SBC dual plane high rise manifold that has the largest port cross section area is the Brodix HV..
You could call or email and ask Brodix.
I'll bet it has the most casting meat to fully port it to increase beyond as cast too.
I'd bet that the Edelbrock RPM air gap Dual Quad sbc manifold is next in port runner CSA size.

There is no real market demand for a Super Sized port SBC dual plane intake as it would have to be quite tall.

[Tom68]

I could be wrong on this but I believe the SBC dual plane high rise manifold that has the largest port cross section area is the Brodix HV..
You could call or email and ask Brodix.
I'll bet it has the most casting meat to fully port it to increase beyond as cast too.
I'd bet that the Edelbrock RPM air gap Dual Quad sbc manifold is next in port runner CSA size.

There is no real market demand for a Super Sized port SBC dual plane intake as it would have to be quite tall.

Look at how high single planes are getting.

I'd call it a limited market, there's applications that might want some mid range and have height.

32 Hiboy.jpg

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[F-BIRD'88]

These applications are where a tunnel ram really shines.

[F-BIRD'88]

Word is Holley/ Weiand is soon going to release a new design tunnel ram style intake for EFI/ carb purpose for the SBC similar to the modern LS platform and Ford v8 Hi Ram EFI series tunnel ram style intakes with removable top.
They have stopped production on the old legacy SBC "Stealth Ram" stuff.
If you don't mind height this new "Hi-Ram" intake series might be interesting.

[Tom68]

These applications are where a tunnel ram really shines.

Now if I could just find that Engine Masters Video where David claimed the Tunnel Ram would make the most torque but in fact the Dual plane did. Can't remember the details, it might have been the most torque below 4000 or something ?

[F-BIRD'88]

The tunnel ram design will make the MOST torque.
The Edelbrock Street Tunnel Ram makes more torque than any as cast out of the box SBC intake.
Porting and or plenum mods on that will show even more output over as cast.

Adding (custom) runner top extensions to the base allows you to add to tuned runner length to tweek where torque is made (RPM) if you don't mind height.
Lots of potential in playing with the plenum top as well.
The full race high rpm tunnel rams make more absolute horsepower at very high rpm. (runners are bigger and a bit shorter)

A dual plane could make a bit more LOW RPM torque on relative mild engines.

[F-BIRD'88]

What is coming from Holley for the SBC may be based on this EFI intake (dual plane design) Uses some of the top plenum components.
It is dual plane design and can have potential with dual carb or 3x2 holley carbs.

[Tom68]

What is coming from Holley for the SBC may be based on this EFI intake (dual plane design) Uses some of the top plenum components.
It is dual plane design and can have potential with dual carb or 3x2 holley carbs.

That's been tested as a dry dual plane.

Take no notice of what's being said.

https://youtu.be/jipoLJToCjM

[F-BIRD'88]

Yes its a "Dry" intake. To run carbs on it will take specific carb tuning for that (it always does)

You can see the pattern that is cast into the plenum like they also had a (2x4) carbed version on their mind on that "mid rise" dual plane intake.
IMHO a casting revision to allow for a bolt on plenum top
would allow for other carb version configurations.
Like a 3x2 "Tri-Power" induction that could be 3x2 carbs or 3x2 EFI throttle bodies.
Tri-Power induction is very sexy with the street rod crowd and also opens the door to a Dual Fuel scheme.
EG: pump gasoline primary and Ethanol/Methanol fuel secondaries.

[RDY4WAR]

The small exit on low rise dual planes can be beneficial to part throttle. The exit is smaller than the port entrance which can help reversion problems. You want the intake runner to be the same size or slightly smaller than the head port entrance, never bigger. Most people running dual planes aren't running big CC intake ports.

[6.50camaro]

When I had and used an Edelbrock RPM Air Gap I did my best to measure average CSA and came up with around 2.40 sq.in. . This was using snap gauges and digital calipers at multiple places in the runners. the runner lengths were in the same ballpark as many of the up swept single planes [ super victor, Hurricane, GM Bowtie, W/P Motown]. So to me the much overstated long runner was the key to better low end torque is false. It is the smaller CSA than the single planes that makes better low end toque. just my .02 cents

[Walter R. Malik]

Edelbrock should bring back the "Smokey Ram" manifold.

[F-BIRD'88]

When I had and used an Edelbrock RPM Air Gap I did my best to measure average CSA and came up with around 2.40 sq.in. . This was using snap gauges and digital calipers at multiple places in the runners. the runner lengths were in the same ballpark as many of the up swept single planes [ super victor, Hurricane, GM Bowtie, W/P Motown]. So to me the much overstated long runner was the key to better low end torque is false. It is the smaller CSA than the single planes that makes better low end toque. just my .02 cents

On a divided plenum dual plane the effective duct length is the combined length of all the 4 runners of that plane.
A dual plane manifold creates a complex multi resoance action. I believe its called a "4th order butterworth" or something like that..

[FC-Pilot]

Edelbrock should bring back the "Smokey Ram" manifold.

…And have bosses to install an injection spider in the plenum. That way you could put your holley body or bodies of choice on and just have them used as throttle bodies. That would reduce the fuel distribution issues of a carb on that manifold. It would make it streetable, while also retaining the old school look if done right.

Paul