Tunnel Ram vs Single Carb ?? - Team Camaro Tech
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post #1 of 15 (permalink) Old Jan 20th, 05, 04:38 AM Thread Starter
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Question

I currently have a 468 BBC and a weiand polished tunnel ram that looks so awsome on the motor, but have heard its VERY hard to make 2 4's work right.. I've heard a tunnel ram with 2 4's if tuned right can make MORE power than a single 4 barrel intake because it distributes the fuel better ... Is this true or can i get just AS MUCH power out of a good single carb intake as i could with the tunnel ram ???? Does anyone out there have any experience or knowledge of this ??
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post #2 of 15 (permalink) Old Jan 20th, 05, 04:46 AM
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Give us the rest of the engine trans (convertor)rear axle specs. Certain tunnel rams are better than others for street manners but they all are a pain especially in the winter. In an all out race engine a tunnel ram will make considerably more high RPM horsepower than a single 4bbl (if the engine can use the airflow) but street cars are a different story.
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post #3 of 15 (permalink) Old Jan 20th, 05, 05:56 AM Thread Starter
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Car is pretty much just for racing ..

Compression is around 13 to 1
Trans is a Turbo 400
Stall is a Hughes 4,000
Cam is a Crower Solid Roller 290/306 -651/677
Heads are open chamber GM 990 rectangular port ..
Heads have had alot of porting done ..
Rear end is a 9 inch with 4.11 gears
Headers are Hedman ceramic coated 2 inch

This is the tunnel ram i have .. It has been port matched to heads .

Weiand Hi-Ram Tunnel Ram Manifold
BB-Chevy
Rectangular Port
2500-8000 rpm
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post #4 of 15 (permalink) Old Jan 20th, 05, 09:22 AM
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Even with your race stuff it still will run better with a single 4bbl. We took the motor out of a 4spd car. 468 13to1 ported 291 heads 266-276 @.050 cam and put it into another car with 5000 convertor turbo 400 4.88 gears and around 2800lbs. It was a stone, ran fine just not very fast. One day I stuck and old C-427 X single 4bbl dual plane and an 850 vacuum carb on. The car was 4tenths and 3 MPH faster. When we put the tunnel ram on the 4spd car it picked up 3tenths and almost 5mph but it had 5.57 gears and was turned over 8000rpm. What I am trying to say is if you need anything that resembles midrange torque a tunnel ram is not for you unless you can find one of the old Offy ones they made for boats. I picked one up but never tried it. They are easy to tell the plenum has dividers in it.

[ 01-20-2005, 08:59 PM: Message edited by: oger ]
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post #5 of 15 (permalink) Old Jan 20th, 05, 09:31 AM Thread Starter
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Thanks you verified what others were telling me.. Im just gonna sale the tunnel ram and linkage .. I've done more research also and i know its not the way i need to go right now... Im just gonna go with an Edlebrock Victor Jr. 454R .. I have a question about my Carb size though, but i guess i will open up a new thread about that ..
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post #6 of 15 (permalink) Old Jan 20th, 05, 02:54 PM
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I have a tunnel ram on my Chevelle and I love it BUT I probably would make more power with out it. My car is a street car adn I can't hook up the power anyway. I did read an article in the last few months in one of my magazines that actually make more power with a tunnel ram on a street SB but the manifold was designed for the street.
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post #7 of 15 (permalink) Old Jan 20th, 05, 04:02 PM
 
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TXZ28 I would use a 1050 dominator pt# 8896. Its the same carb Reher-Morrison uses on their 468 BBC. It should already have pretty close to optimal jetting out of the box.
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post #8 of 15 (permalink) Old Jan 21st, 05, 03:09 AM Thread Starter
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Quote:
Originally posted by BDS 502:
TXZ28 I would use a 1050 dominator pt# 8896. Its the same carb Reher-Morrison uses on their 468 BBC. It should already have pretty close to optimal jetting out of the box.
Thanks, I came across a good deal on one so im gonna try it out .. Thanks for all the info ..
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post #9 of 15 (permalink) Old Jan 21st, 05, 01:53 PM
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It has always seemed that the biggest contributing factor in using tunnel rams is that everyone wants to over-carburate them. If you use a "street" tunnel ram, and put small carbs on it, so that you keep the velocity of the fuel mix high, you can make alot of power. Either use vaccuum secondary carbs, or better yet, use a set of predators. But, again, the secret to tunnel rams is small carbs, and high velocities. Some guys have been very successful at using a set of 2 barrel carbs, also. Just a thought.
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post #10 of 15 (permalink) Old Jan 21st, 05, 04:14 PM Thread Starter
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Quote:
Originally posted by nothinbuttaillights:
It has always seemed that the biggest contributing factor in using tunnel rams is that everyone wants to over-carburate them. If you use a "street" tunnel ram, and put small carbs on it, so that you keep the velocity of the fuel mix high, you can make alot of power. Either use vaccuum secondary carbs, or better yet, use a set of predators. But, again, the secret to tunnel rams is small carbs, and high velocities. Some guys have been very successful at using a set of 2 barrel carbs, also. Just a thought.
Yeah thats what i planned on doing, but my concern is that since its a tunnel ram will all the power it produces not come into affect until the top end ??? Can the tunnel ram produce any power down low ??
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post #11 of 15 (permalink) Old Jan 24th, 05, 04:24 PM
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It depends upon what type of tunnel ram you get. All out race, yes, power on the top end. Edelbrock makes a "street" tunnel ram that has a rpm rating of 3000-7500. Weiand makes a "street" ram with a rpm range of 2800-7000. That seeems a little better. The same rpm range as most hipo single 4-barrel intakes. There used to be someone (offy, or edelbrock) that made a wonderful "marine" tunnel ram that had a low rpm range, something like 2500-6500. But I can't find it listed anywhere. I'm sure they show up every now and then on e-bay. I'm going to try to go through some of my really old catalogs and see if I can find who did make it, and it's part#.
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post #12 of 15 (permalink) Old Jan 25th, 05, 03:22 AM Thread Starter
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Quote:
Originally posted by nothinbuttaillights:
It depends upon what type of tunnel ram you get. All out race, yes, power on the top end. Edelbrock makes a "street" tunnel ram that has a rpm rating of 3000-7500. Weiand makes a "street" ram with a rpm range of 2800-7000. That seeems a little better. The same rpm range as most hipo single 4-barrel intakes. There used to be someone (offy, or edelbrock) that made a wonderful "marine" tunnel ram that had a low rpm range, something like 2500-6500. But I can't find it listed anywhere. I'm sure they show up every now and then on e-bay. I'm going to try to go through some of my really old catalogs and see if I can find who did make it, and it's part#.
Yeah i have the Weiand street tunnel ram with 2800-7000rpm power band .. I was gonna use 2 holley 650's, but i didnt know if i should use double pumpers or ones with vacuum secondaries ?? My biggest issue is i DONT want to have to buy 3 carbs .. If the tunnel ram doesnt work out then i'll have to buy another intake and another carb !!! I dont have the money to experiment with that right now ..

[ 01-25-2005, 05:32 AM: Message edited by: TXZ28 ]
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post #13 of 15 (permalink) Old Jan 25th, 05, 08:55 AM
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Well, the best tunnel ram carb for performance is the Holley 660 center squirters. But for the street, the mileage is aweful. What are you going to use it for?
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post #14 of 15 (permalink) Old Jan 25th, 05, 09:00 AM Thread Starter
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Gas milage is the least of my worries lol ... This is about a 90% strip car .. I just want to make sure i dont over carb the motor ..
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post #15 of 15 (permalink) Old Jan 25th, 05, 09:17 AM Thread Starter
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Thats ok ... I'll pass on the dual carbs.. I just looked up the Holley 660's and they are 500 dollars a piece ... Which means i would be paying a 1000.00 dollars just for carbs... I can get a brand new 1050 dominator for 600 bucks ..
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