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Best dual plane for my Magnum 5.9?

Posted By: gregsdart

Best dual plane for my Magnum 5.9? - 01/15/17 04:56 PM

I plan on putting the following cam in a boneyard 5.9 Magnum engine, for my street dart. 279 duration, 225/225/106 @ .050 with .480 lift. There are different runner sizes available from what I here, with the Edelbrock airgap being the biggest, and the Pro products ( chinese knockoff) being the smallest. I want lots of torque in the 2500 to 4000 area because the converter will be a fairly tight street unit,(2400?) with the car being primarily a street car.Has anyone done any back to back comparisons on these, dyno or drag strip tests, and what were the conditions like stall and traction?
Posted By: Locomotion

Re: Best dual plane for my Magnum 5.9? - 01/15/17 09:04 PM

I have no experience with these, but....

Trust in quality may be a concern with Pro Products. I would have thought that port size would be similar because of it being an Air Gap "copy". There still is a M-1 dual plane from Mopar for smaller ports than the Edelbrocks.

http://www.manciniracing.com/mopduelplanm.html

Maybe to help make an educated choice, search to see if there are any dyno numbers using those intakes in LA applications. The HP/torque curve numbers should be similar to their Magnum counterparts.

Any concerns using an Air Gap style without heat crossover in the winter months?
Posted By: cudadoug

Re: Best dual plane for my Magnum 5.9? - 01/15/17 09:22 PM

Didn't Dulcich (sp?) do a intake comparison for small blocks? I read it in print somewhere and IIRC, the Eddy Air Gap was the overall champ.
Posted By: Locomotion

Re: Best dual plane for my Magnum 5.9? - 01/15/17 09:48 PM

Originally Posted By cudadoug
Didn't Dulcich (sp?) do a intake comparison for small blocks? I read it in print somewhere and IIRC, the Eddy Air Gap was the overall champ.


Thanks, I forgot about that one.

Small block Mopar dyno tests. LA
Posted By: Blucuda413

Re: Best dual plane for my Magnum 5.9? - 01/15/17 11:06 PM

If your going to street use go "Street Dominator" vs "Strip Dominator" The inside of these manifolds are exactly the same but the street version has water under it and the strip unit does not.
Posted By: Locomotion

Re: Best dual plane for my Magnum 5.9? - 01/16/17 01:10 AM

Blucuda413, You just reminded me that the Magnum heads don't have a heat crossover! I forgot that in an earlier post. frown

But as far as internal passages, the "Street vs Strip" Dominators, they are only the same on the W-2 versions. For standard beads, Edelbrock RPM with and RPM Air-Gap are the same internally.
Posted By: Blucuda413

Re: Best dual plane for my Magnum 5.9? - 01/16/17 01:15 AM

Myron, I didn't even think about that because the 2 I compared were W2 versions. Thanks for bringing that out.
Posted By: Anonymous

Re: Best dual plane for my Magnum 5.9? - 01/16/17 01:27 AM

There is a pretty big diff in runner volume on the eddy vs the China deal air gaps -- I measured it on a SBC one time --can't remember but is was a lot--guessing that the Mopar version is similar--the runner cross sections and overall volume was lots smaller on the china job--I can't see how you would be giving up much Tq with the eddy--it would be my choice
If you have both maybe tape them up and CC--hey bet you can see the diff with a tea pitcher and won't need a burret LOL
Thinking small carb may be helpful vs. a 750
Posted By: gregsdart

Re: Best dual plane for my Magnum 5.9? - 01/16/17 02:05 AM

It is looking like the Eddy AirGap is the better choice at this point. I notice on Dulsich's dyno results it isn't far behind at 3,000 and is up as much as 20 hp mid range,and 24 hp up top, although that is with a bigger cam than I have,and better heads than I plan on at this point.
Posted By: mphsmitch

Re: Best dual plane for my Magnum 5.9? - 01/17/17 03:12 AM

For what its worth Ive had both of the Crosswind and the Air Gap intakes on my truck when it had the stock bottom end 360 magnum in it. There was no difference in ET at the track.
Posted By: B3422W5

Re: Best dual plane for my Magnum 5.9? - 01/17/17 04:37 AM

I have a professional products dual plane on my 318 magnum.
Works good.
Best results so far in my signature. My cam is 231/238@50
Posted By: 71yelladustr

Re: Best dual plane for my Magnum 5.9? - 01/17/17 05:07 AM

Not to hijack, but B3442W5 please tell us more about your combo. That et in your sig is impressive!!
Posted By: B3422W5

Re: Best dual plane for my Magnum 5.9? - 01/17/17 06:02 AM

Originally Posted By 71yelladustr
Not to hijack, but B3442W5 please tell us more about your combo. That et in your sig is impressive!!


It's an engine masters build.
10.44 compression. Ported magnum Rt heads. 950 carb, aforementioned hydraulic cam.
Diamond slugs, scat rods, trick lightened 340 crank. 30 over 318 for 323 cubes.
Cheapie 1/5 8 headers, 904, tight 8 inch converter, 28 inch radial with 4.10 gear. Shift it at 6200, traps about 6. Could use a little more gear but I drive it everywhere.
All steel car, 310 pound driver. Nice attention to detail on the short block build, several oiling mods, and rocker shaft upgrades.
But, she has a dinky cam and not much compression, think there is still more.
Posted By: gregsdart

Re: Best dual plane for my Magnum 5.9? - 01/17/17 10:46 PM

Thanks to all who gave feedback😀 any more info that would relate to this build is welcome!!
Posted By: Adobedude

Re: Best dual plane for my Magnum 5.9? - 01/18/17 04:47 PM

Don't use the stock magnum valve springs, barely good enough for the stock cam, then the two piece valves are at risk...Replace the timing chain too.
Maybe you know all this.
Posted By: gregsdart

Re: Best dual plane for my Magnum 5.9? - 01/18/17 05:55 PM

Thanks Adobe. I will check with hughes when i oder the springs to see about the stock valves.
Posted By: sshemi

Re: Best dual plane for my Magnum 5.9? - 01/18/17 06:03 PM

Whatever you do do NOT remove the heads!
Youll only find tons of cracks in the valve seats and want to replace them...
Dont ask me how i know:-)
It sucks as the magnum heads look so much better than la heads.
Im positive a very small amount of porting/clean up will make them flow very well.
But they all seem to have cracks and throwing time and money on cracked heads is hard to motivate.
Posted By: gregsdart

Re: Best dual plane for my Magnum 5.9? - 01/18/17 06:11 PM

If i do pull them and they need work it will be time for a set of EQs. The value will be there when i sell the motor,if that happens.
Posted By: sshemi

Re: Best dual plane for my Magnum 5.9? - 01/18/17 06:37 PM

Thats what i ordered from hughes. Value is good but it cracked my budget.
Posted By: HotRodDave

Re: Best dual plane for my Magnum 5.9? - 01/18/17 08:04 PM

If cracks make you loose sleep and you are gonna pull the heads have the EQs ready, your heads are cracked. If you have seen thousands of these heads running just fine with cracks in them like I have don't worry about it.

Also I have built tons of these engines with bigger cams than that that see daily use under severe conditions and never seen a stock valve fail except the ocasional burnt valve when nearing 300,000 miles. I am currently running .575 lift and 222@.050 duration 12 to 1 compression in my truck with the stock valves plenty of 6500 RPM blasts and no issues.
Posted By: Adobedude

Re: Best dual plane for my Magnum 5.9? - 01/18/17 08:25 PM

For your viewing pleasure....Not my motor.
As I understand, it's only the intake valves that are two piece, I might be wrong.
But like I said..."At Risk"...I know of more than one occurance. I'm not taking that risk. "Do you feel..Lucky?"

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