hello wat is the difference do wr get more power what is the best ? i have a 340.

thank you

Dual plane usually more/better low end and the single plane for more top but may take away for the bottom.

and a LD340 IS OK what is the best compromis ( i don't know in english)

IMO an excellent choice. Very good manifold. I use one on this car in the pic.

what is IMO ? where i can find it ?

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what is IMO ? where i can find it ?

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Generally if your motor spends the most of it's time (say 85-90%) on the street between 2500 and 4000 rpm a good dual plane like the Edelbrock Performer RPM or The old LD340. If you run a lot of gear, a 4 speed or a lot of stall 3200+ Generally a good single plane like the Holley Strip Dominator or the Eddie Victor 340 will work better.....by better I mean will produce the highest average torque throughout the powerband you run the most. The compromise is how much low end torque are you will ing to lose to gain how much above say 4000rpm where a single plane will start to show an advantage....every combination is different but with a mild 340 in an A body the performer RPM (or it's air gap alternative) is a pretty good choice unless you have really good heads becuase the intake alone doesn't make the big top end power pay off interms of ET...it's the combination of compression, head flow induction (intake and carb), exhaust flow and gearing.

I would run the performer RPM Air Gap...its the best compromise of everything. I have seen several dyno tests where they make almost as much peak HP as the single planes but don't really give anything up down low to the other dual planes.

I think it looks cool too!

What's the difference between the LD340 & the Air Gap? Alum vs cast?

LD340 is old school technology and the Air gap is the same basic intake as the RPM only with an 'airgap' under the plenum/carb to in effect make for a cooler fuel charge.

ok so go fot ld 340 ! somebody have one ? AND DO I HAVE TO HEEP ME HEADERS OR LOOKING FOR 4 BY 1 AND THE CARB ? which one ? THE BEST SIZE FOR EXHAUSt ? thanks

Go for the Ld340 if you can find one, a set of TTI step headers and a 2.5" exhaust.
Works great on a street car.

I am not a fan of the dual plane intakes on any old car or engine I have ever owned, but I have to say, I purchased a Air gap, and modded it a little, and the darn thing flies....Removed the logo, port matched it, ground down the center divider, and blended the entry ways with a 1" open spacer. I still need to do the cross cooling thing, but ran out of time when I had it off last.