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Tunnel Ram & 2 4's

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Old 11-06-2012, 12:27 AM
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Tunnel Ram & 2 4's

Why don't i see this on bigger cubic inch marine engines ? Would this help a 540ci and bigger breathe ? I just need to know . deep
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Old 11-06-2012, 06:41 AM
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The RPM range for tunnels rams is higher than most boats use...
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Old 11-06-2012, 07:53 AM
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Every dyno test I've seen shows that tunnel rams are as good as dual plane on the low end and better than single planes on the top. I know Engine Masters magazine did some side by sides and the tunnels worked best overall by a significant margin.
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Old 11-06-2012, 09:26 AM
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Originally Posted by ThisIsLivin View Post
Every dyno test I've seen shows that tunnel rams are as good as dual plane on the low end and better than single planes on the top. I know Engine Masters magazine did some side by sides and the tunnels worked best overall by a significant margin.
It would be nice to see some real world numbers by our own engine masters . Would there be an advantage only spinning the rpm's to 6,000 ? Thanks
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Old 11-06-2012, 10:53 AM
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Idle characteristics?
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Old 11-06-2012, 11:15 AM
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I have a tunnle ram on my 588 ci 14 to 1 engine idle in cold weather can be a little fun works best in upper rpm .

When i built my 588 i went big bore short stroke so i could rpm it to take advantage of the tunnle ram.

Nothing like a big chevy at 6800 rpm sounds cool.

Go to 2012 loto part 1 on you tube we are about the 15th boat running sounds cool.
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Old 11-06-2012, 03:34 PM
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Originally Posted by gary cook View Post
I have a tunnle ram on my 588 ci 14 to 1 engine idle in cold weather can be a little fun works best in upper rpm .

When i built my 588 i went big bore short stroke so i could rpm it to take advantage of the tunnle ram.

Nothing like a big chevy at 6800 rpm sounds cool.

Go to 2012 loto part 1 on you tube we are about the 15th boat running sounds cool.
That's definitely a chest thumper bro !! Nice work . Would you post a pic of your engine ?
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Old 11-06-2012, 05:42 PM
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We converted tunnel rams to EFI, they make good power. I would think with the right carbs and proper tuning they would work just as well.
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Old 11-06-2012, 07:54 PM
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Originally Posted by GPM View Post
We converted tunnel rams to EFI, they make good power. I would think with the right carbs and proper tuning they would work just as well.
I agree i took the boat out the day i left for loto with a fresh engine drove it around for 20 min to break it in did a couple of speed runs with wide band on it to make sure air fuel was ok.
We broke a 100 mph so i new i could step up the record from last year so i did no more tuning that being said it ran ok with out of the box gary williams carbs and would idle around at 1000 rpm .
If you fuel inject it a lot of problems go away.
But to get the real advantage of a tunnel ram be ready to turn some rpm so dont scimp on the valve train.

Last edited by gary cook; 11-06-2012 at 07:56 PM.
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Old 11-06-2012, 08:17 PM
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JimV (Valako) runs a Holley Dominator tunnel ram manifold modified for EFIon his 565 with twin 1000cfm throttle bodies. I believe the dyno was [email protected] And it was not lacking torque. They make power. Last year he tried twin 750 carbs and lost power.
Attached Thumbnails Tunnel Ram & 2 4's-jim.jpg   Tunnel Ram & 2 4's-jimv.jpg  
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