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Old 06-17-2008, 11:24 PM
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Tunnel Ram on a sbc

Still deciding whats gonna sit on top of my 383 stroker. So far its goin good the block checked out and machining has begun. I was wondering if tunnel rams kill as much tourqe as people say they do? Also has anyone else built a tunnel rammed 383, what kind of combination are you running and what kind of power are you getting? I'm looking at either a Dart or Weiand tunnel ram my heads are a set of trick flow 170's with some port work and 2.02/1.60 valves and the cam will be a comp roller either xr270 or xr 274. Any suggestions greatly apreciated. thanks, Jake

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Old 06-18-2008, 12:47 AM
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A tunnel ram makes a lot lot of torque in the rpm band that it is tuned to.
3500-7500rpm (street tunnel ram)
A race type tunnel ram has shorter, larger runners and is tuned for an even higher rpm band. (6000-9500rpm) (pro stock)
A street tunnel ram comes on strong and makes a ton of torque at around 3000-3500rpm, with strong power to well over 7000rpm.
If you want a motor that makes torque right off idle like a stock motor does, you do not want a tunnel ram.
If you want to cruise down the road at 1600rpm, (Typical 3.08 gears and stock converter and overdrive) you do not want a tunnel ram.
Your little 270deg cam is too small for a tunnel ram (if you want it to make its best power)
You need a healthy cam 240+++++@.050", lots of compression, lots of rear gear and a high stall converter (3000 minimum) The tunnel ram (induction pulse wave inertia ram tuning) and camshaft/valve event timing and exhaust system must all work together to make power.

Will it make a lot of torque? yes, More than a single 4 bbl single plane manifold, within in its intended rpm range. 3000+++rpm.
Will it make a lot of torque at 2000rpm? No. The runner cross section area is too big and the tuned runners length is too short for high torque at 2000rpm?
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Old 06-18-2008, 04:40 AM
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i have a 383 with a weiand tunnelram in my 87 S10 i use a comp cam 292hyd.basicly stock heads (202 and 160 vavles installed) till i can get new ones i have a 3500 stall converter i put in a eagle stocker kit for the bottom end. the engine idles at 1300 any lower then 1000rpm and it stalls, or spits sputters. but I built my manly for cruse nights and shows tunnel rams look alsome, thats for sure and i have no complents with mine. pics of my s10 while it was flat black now in the shop getting sprayed HOK pravo purple metal flake. all depends what u wanna do with your ride i guess. go with the tunnelram
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Old 06-18-2008, 12:27 PM
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smrat, what kind of power are you making with that thing. Ever had it on a dyno? What kind of cam and gears are you running? Does it cruise down theroad allright, my car is only a once a week driver not much more. The weiand tunnel ram is rated at 2500-8000 rpm i believe. And i think its the one i would like to use. Plus it would look so good with a blower style scoop out the hood of my car
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Old 06-18-2008, 04:30 PM
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Just be careful how large the carburetors are. For the street I use a pair of 390cfm Holley carb. in my chevelle. I would change the primary jets to 57
and a 6.5 single stage power valve. I used a blue pump cam and set it for #2 setting. With two carburetors you will get 780cfm. You will get good low end torque and strong midrange and top end. I do not recommend 450cfm for the street unless you are racing it at the tracks.
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Old 06-18-2008, 06:22 PM
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The weiand manifold is available in a single carb application so i was thinking of going that route with either a 750 or 850 double pumper holley.
[IMG]C:\Documents and Settings\Home\My Documents\My Pictures[/IMG]

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Old 06-18-2008, 07:12 PM
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Jake
You may be able to make it work. I recently had a tunnel ram combo on my street 355ci Chevy and it had torque as soon as you get on the gas through 7000rpm. It had 10:1 pistons, 461 fuelie heads ported with 2.02/1.60, 3000rpm stall, and 4.88 gears. The carbs were two 600cfm vacuum secondaries with 29" x 18.5" tires and the cam was a solid Isky grind with 254' duration. It idled at 900rpm with a mean cam lope and the low end would pull right off idle. The only problem I ran into was tuning the 600's...it took awhile. Jetting, squirters, pump cams and secondary activation took awhile to sort but if you're good with Holley's it shouldn't be a problem. In the end I added two NOS plates and stayed on the conservative side with 150 shot total. That engine would scream with rpm's !! I have since sold that motor to a circle track racer who buzzes the rpm's every weekend.
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Old 06-19-2008, 12:07 AM
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Well i've alreay got 4.10 gears in the car right now and will probably stay there unless i get around to putting in a ford 9 inch then i can go to what ever the motor wants. I'll be running a 3500 rpm stall for shure if i decide to stay with th automatic and a trans bake or line loc. Compression is gonna be 10 maybe 10.5 if i can get away with it on aluminum heads? Eventually it'll have large 1 3/4 headers and 4 inch exhaust out the side. So that leaves the cam? What do you guys think? definatly roller, Would like to be around the 500/500 mark if possible so my 77 camaro will realy boogie down the strip. Im also planning on taking her to a dyno for final tuning then ill know what i really got Thanks so far, keep the great advice comming
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Old 06-19-2008, 01:03 PM
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Anyone got any cam sugestions?
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Old 06-19-2008, 03:46 PM
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I ran two 600 on my 350,Did OK,But then I went to two 450's And it came alive!!! Two 450 is 900 cfm's Most good motors run very good at about 750 to 850.
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Old 06-19-2008, 05:20 PM
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What about a single 850, do tunnel rams run good with single carbs i know weiand offers theres with a single carb top?
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Old 06-19-2008, 09:00 PM
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Tunnel ram

Single four-barrel tops for tunnel rams are known to be about the worst intake set-up you can bolt together The best engine builder's in the country can't make them perform, mixture distribution is terrible, the four inner cylinders are pig rich and the four outers are lean.
The only set-up that works is a custom built sheetmetal ram that actually looks more like a 10" tall single plane intake.
Why they even still sell the single four tops is beyond me, maybe it's a case of giving the customer what they want despite the fact that it is about 6 steps in the wrong direction
Tunnel Ram is a waste of time unless you are targeting the additional power that they can make in the 6500-8500 rpm range, and it won't be with one of the typical "street rams" that clutter up Ebay.
The four Tunnel Rams that actually work are--
Edelbrock Pro Ram and Pro Ram II ( both out of production)
Weiand Team G Super Ram (designed by Grumpy Jenkins, out of production)
Edelbrock Victor Ram
Holley Pro Dominator Tunnel Ram
Go to the dragstrip and see if anybody fast is running a street tunnel ram, I can virtually gaurantee you won't find one

Last edited by ericnova72; 06-19-2008 at 09:05 PM. Reason: More info
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Old 06-20-2008, 07:56 AM
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Originally Posted by ericnova72
Single four-barrel tops for tunnel rams are known to be about the worst intake set-up you can bolt together The best engine builder's in the country can't make them perform, mixture distribution is terrible, the four inner cylinders are pig rich and the four outers are lean.
The only set-up that works is a custom built sheetmetal ram that actually looks more like a 10" tall single plane intake.
Why they even still sell the single four tops is beyond me, maybe it's a case of giving the customer what they want despite the fact that it is about 6 steps in the wrong direction
Tunnel Ram is a waste of time unless you are targeting the additional power that they can make in the 6500-8500 rpm range, and it won't be with one of the typical "street rams" that clutter up Ebay.
The four Tunnel Rams that actually work are--
Edelbrock Pro Ram and Pro Ram II ( both out of production)
Weiand Team G Super Ram (designed by Grumpy Jenkins, out of production)
Edelbrock Victor Ram
Holley Pro Dominator Tunnel Ram
Go to the dragstrip and see if anybody fast is running a street tunnel ram, I can virtually gaurantee you won't find one
You don;t see them on your typical bracket racer cause a bracket racer by definition wants to run consistant et's. Most guys don't have a clue how to set them up properly.
Using small cfm carbs makes it easy to tune and drive at low rpm (where the tunnel ram doesn;t makes its power anyways) and works for cruisers and show cars. But if you want the power advantage that the street tunnel ram can make over a single plane Vic Jr manifold makes, you need to use much larger carbs to get this. You're typical carb cfm choice math formula will not get you the right carbs size. (easy to drive but won't have the power.)
Just as the Pro Stock/ Modified Production class eliminator full race tunnel rams need twin 1050-1350 dominators (2300-2500+cfm carb capacity.)
The street tunnel ram needs a good bit of total cfm to see the power advantage.
1300-1500cfm for the SBC.
Most don't have to patience or understanding to bother tuning them right.
90% of the bracket racers at the track use the same old same old cookie cutter single 4bbl single plane manifold setup cause its simple to tune.
Who wants to change 8 jets and 16 air bleeds to correct for weather on a bracket car.
They don't run the old Modified Production drag classes that used to use the race version T ram that the Edelbrock street ram and Weiand Hi ram were designed from.
Needs good heads, a serious cam 248 to 270@.050 solid or roller cam and 10:1 ++ compression. Open, tuned, big exhaust headers. Makes serious power from 3500 up rpm.
The long, raised runners and raised carb plenum takes a long time to warm up for street driving (or even racing) makes tuning a bit of a challenge if you don;t understand whats going on under the carbs. (Operational manual chokes really help street driving and warm up)
Can make 20 to 40 more HP than a Vic JR. The old full race, Prostock T Rams would make 100++ hp over a single plane manifold.
Just as you don't see other multi carb setups like Cross Rams etc on the typical bracket car, (90% of the cars at the track run some form or another of "dial in" racing today)) the power advantage is offset by the simplicity and consistency of a single 4bbl set up. Dial in bracket racing is all about consistancy, not setting NHRA/IHRA class records.
But in the old N/A "heads up run what you brung and hope you brought enough" classes back in the day where the guy who finishes first, wins, and takes home the $$$, the tunnel ram is king.

You'll see a lot of the BBC and SBC Edelbrock street ram and Weiand Hi ram and Offy 2x4 Tunnel Ram setups used on race/ski river racer boats (both prop and jet drive) that run flat out WOT and want maximum possible N/A horsepower.

A good example of a street tunnel ramed SBC making 20peak hp and 30+ average HP ( and torque) more than a single 4bbl

Last edited by F-BIRD'88; 06-20-2008 at 08:42 AM.
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Old 06-20-2008, 10:29 AM
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My tunnel ram setup

This is what my using in my 69 chevelle 355cid edlebrock TR1X and a pair of Holley 390cfm. On the secondaries, I'm using metering blocks and change from a single feed to a dual feed setup. I've got a 11:1 406sbc that I'm replacing and using AFR heads with the same setup I'm using on the 355.
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Last edited by lg1969; 06-20-2008 at 01:07 PM.
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Old 06-20-2008, 09:22 PM
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i have a 3500 B&M stall converter, 456 rear gears.i never tryed it on a dyno. i built it mostly for cruse nights and shows. it runs great but likes to drink gas too. sometimes i cheat and loosen the rear carb linkage srcew so the rear carb doesnt work till i need it. i dont notice any difference w/o the rear carb hooked up .if you use the wiend tunnel ram, you have to you use a small dist. mine is a MSD mech advance, i forget what the part number is now, call Jegs or Summit they can tell you.

Last edited by smrat; 06-21-2008 at 04:39 AM.
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