tunnel ram vs modern single plane

Old 12-06-2009, 08:13 AM
  #1  
chevyart
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Default tunnel ram vs modern single plane

one of the guys on our forum swears that a tunnel ram(on a street car with moderate horsepower outperforms and out dynos and out does everything over a single plane. i think maybe a tubbel ram may perform well in a world above 7500 rpms, but down low i just think its a waste and only may look impressive. what do you guys think. he also states that 2 600 cfms carbs on a tunnel ram only equals 600 cfms and not 1200 cfms. what is that statement all about i dont ubderstand that thanks chevy art
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Old 12-06-2009, 02:27 PM
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JimmySmith
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I ran a OLD edelbrock TR on my 350 with 2 600 vac sec and it was about a tenth qoicker than my single plane and 850 cfm, I had to get rid of the power valves to get it to run consistant . Later J.Smith 4621 racing
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Old 12-07-2009, 06:40 AM
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We ran some dyno test on a BBC with a short height tunnel ram and two 700 cfm vacuum secondary carbs. The carbs had 50cc pumps in the front and it was amazing how flat the torque and HP curve was. Upon hit of the throttle, it received the fuel and air flow of a 700 double pumper, but then had the vacuum secondaries to open as required to build rpm.
Dave
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Old 12-07-2009, 11:38 PM
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cepx111
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Default Re: tunnel ram vs modern single plane

Originally Posted by chevyart
one of the guys on our forum swears that a tunnel ram(on a street car with moderate horsepower outperforms and out dynos and out does everything over a single plane. i think maybe a tubbel ram may perform well in a world above 7500 rpms, but down low i just think its a waste and only may look impressive. what do you guys think. he also states that 2 600 cfms carbs on a tunnel ram only equals 600 cfms and not 1200 cfms. what is that statement all about i dont ubderstand that thanks chevy art
As far as a tunnel ram on the street, I agree that it would be a dog, an old style one anyway, they are best suited to high rpm reving.

As far as the statement 'he' made about the cfm, he is wrong, if all 8 barrels are open (WOT) the engine is sucking air via 1200cfm's worth of carbueration.
On a side note:
If I was wanting to build a moderate level street car engine with good driving manners and performance I wouldnt even consider a tunnel or a single plane.
A dual plane intake like a performer RPM or performer RPM air gap would be a much better choice.

JMO, Cp
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Old 12-08-2009, 09:39 PM
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chevyart
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Default tunnel rams

hey cepx111. thanks for the info, and i agree with you 100% about the air gap manifolds over the tunnel ram. i just about said the same thing to the guy who was really praising the tunnel rams. his car really cant perform very well with that tunnel ram system. he probably is in denial chevy art
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Old 12-09-2009, 09:32 AM
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cepx111
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Default Re: tunnel rams

Originally Posted by chevyart
hey cepx111. thanks for the info, and i agree with you 100% about the air gap manifolds over the tunnel ram. i just about said the same thing to the guy who was really praising the tunnel rams. his car really cant perform very well with that tunnel ram system. he probably is in denial chevy art
Exactly.... But hey, they're retro man 8)
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Old 12-19-2009, 05:42 AM
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Pwmax
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Actualy, a tunnel ram with carbs that are set up right, are not a dog on the street, and almost always make a big boost in tq. Its about line of sight, a direct straight shot, and, the runners are longer, which boosts tq. 99% of the time tunnel rams get a bad rap, is because the carbs and distributor, aren't set up right, and the run like crap by default, it has nothing to do with the tunnel ram.

Frank
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Old 12-19-2009, 06:30 AM
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lively
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i have run tunnel rams on my sbf along time and still feel they will hold their own if everything is matched to them[ timing/ carbs/ rear gear ratio/headers/] plus--THAY ARE GREAT LOOKING --the only thing better looking are 8 injector stacks or a sweet liitle 6-71 BLOWER[ NOT UNLESS YOU HAVE TWIN TURBOS STICKING PARTWAY THRU THE HOOD!!!]

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