air gap vs ld 340

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hockeydad1189

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hi am looking at a ld 340 intake for my 72 340 .are they any good for a mostly street car ,what is the rpm range the engine is not overly built about 9.5 comp hi po exhaust manifolds is there any h p improvement over 1970 stock intake any help or info would be helpful. is the air gap better or about the same
 
the LD340 is a very good intake. I have had several of them on my 340 cars over the years. On a mild street car like yours, It works perfect. I would venture to say there is only maybe a slight gain in performance over a stock thermoquad intake, but there is a good weight savings over an iron intake, and if you want to keep the engine stock in appearence, you can always paint it engine color. They look a lot like a factory intake. The airgap , I belive, would show better performance gains, especially on a modified engine.
 
I went from an LD340 to a air gap on my 10.2:1 340 with a MP .284/.484 cam and the only difference I noticed is that it seems a little more cold blooded. No noticeable HP gains when driving.
 
If you have one I wouldnt bother switching to the other. I like the LD340s myself.
 
Well, going to aluminum will save you at least 25 lbs off the front end. It may help you if you have hot restart (fuel boiling) issues as well.

I'm surprised you didn't bring up the performer rpm. Seems like that would be a good option for you as well as it still has an exhaust crossover, and is a little shorter...and is also available new.
 
Weight loss is the main thing you will gain. All are dual plane so good low end grunt. If you want more you have to go to headers, cam and intake.
 
i switched to the airgap on similar set up to swinger340
it definetly is cold blooded but if you can't sit in your car for a few minutes you might as well not use it. you have to modify the throttle bracket a little other than than it fits with just room to close hood without hitting air cleaner.
without dyno i couldn't confirm but on my set up it feels different than the ld. especially 3500 rpm up. rated 1500-6500 areas for premium range.
 

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out of all the intakes ld340 ,air gap or rpm which one will give the biggest kick over stock
 
I like the LD340. I am old school old guy though. My 2 cents. It also depends on carb you are running, Ld340 is square bore and I believe the performer is a spreadbore.
 
They are all going to be close in performance. If you want one that looks some what stock the LD340 is the way to go.

This motor made over 450hp on the dyno with a LD340
 
What carb are you running now? I'f it's 600-625 range, stepping up the cfm to 700-750 or so will probably give you more gain then a intake swap.

Also, the LD-340 is a very good manifold.
 
LD 340 , one of the better intakes out there , plus you can use the stock choke .
 
Air Gap and Performer RPM are the same internally. I'm sure it gets pretty cold in Mass. so the Performer RPM with crossover would be best. LD 340 has always been an excellent intake. Choose between LD 340 and Performer RPM based on best deal.
 
Man, this seems to go on and on forever. The RPM, RPM AG and LD340 are all basically the same intake. They will all make the same power, give or take a few hp. Same goes for the Weiand Stealth intake and the Action Plus.

The Performer intake is no better than a stock 340 intake, only its aluminum and lighter.

We did 2 340 stokers this summer, one with an RPM(non ag) and a Stealth. Both made 560HP and 550TQ.

Go with whatever one you can get the best deal on, LD340's seem to be as much as a new intake these days, at least people are asking as much. And thats crazy.
 
..but the LD340 is hysterical...oops,.historical!
i think the trip from the carb 3 or 4 inches to the intake valve was figured out 40 years ago.
 
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