Just wondering if anyone is running a tunnel ram manifold and how they like it, what kind of power gains your getting and the fuel mileage. BBC or SBC.... Also what carbs you are running? Im slightly considering this on a BBC Build up.

Years ago I ran one on a BB bracket car with a 4spd. I found it to be far superior to a single plane manifold with a Dominator but only on a car with a manual trans. We tried it on a much ligher car with a 400 and a 5000 convertor. Ended up going to a dual plane and an 855 Holley. The tunnel ram simply didn't have enough torque at 5000 rpm to make the auto trans setup work. There are (boat tunnel rams) as we called them with dividers in them that will work at lower RPM but I don't think you will see a gain over a good single 4bbl with them.

If your concerned about fuel mileage, you dont have enough motor for a Tunnel Ram. It will sure look neater, but a single or dual plane high rise will out perform it. I ran one a few yrs. back on a SB w/ 2 660's that I revved to 8200 I switched to a strip dominator with one 850 and picked up some in ET, MPH stayed about the same, but it was WAY more consistant.

I ran one on my 396 some years ago. I had 2 Holley 600cfms with vacuum secondaries and the lightes spring I could get in them. I really loved it when you mashed on it it would shove you back in the seat. I did have idleing problems that I never fixed. It would surge betwwen 1000 and 1500 RPM at idle. I blocked off the power valve trying to fix it but it seem that anything I did would not work. I drove this car 13 miles to work every day, When we would get a heavy down pour the intake would suck in water. So it just had to go. Ah,but to look at it, it was a bad looking SOB. Also if you want any vacuum signal...FORGET IT!

http://www.bigblock67chevelle.com/engine004.jpg?

http://www.chevelles.com/showroom/AdamLym/Engine2004-small.JPG

I'll post details when I have more time, gotta go to class now

tongue.gif :cool: graemlins/thumbsup.gif

Too Cool Mr. Layman, ROCK ON!!!!!!!!

awesome motor adam

I ran one on the street years ago on a rectangular port 396. It was an '68 Nove x-race car converted into Pro Street duty. I literally used it as a daily driver for several years, but only had to go 20 miles round trip.

I was using an old Weiand one with the divided plenum. I used 660 center squirters that I worked over well enough that they were fantastic. They idled fine and of course mid/top end was fantastic.

The car had a 4 speed and 5.36's, but it did have 32" tires on it Ran mid 10's on pump gas and pulled wheelies great!


They can be made to work on the street if you do some tuning. It will like LOTS of initial timing. In fact I cruised around with 55* total in it and it really helped street manners. I used a homebuilt timing retard system to pull it back to 38-40 under full load in 3rd and 4th gear.

JIM

55 thats pretty crazy

I've driven a Cutlass with a 455/Offy tunnel ram..had 660 center squirters too..car had a TH400/3500 stall and 4.10's w/ladder bars.. was fun to drive on the street graemlins/thumbsup.gif
it didn't drive any different other having a very stiff gas pedal (Note:Gene,if you're reading this,stiffer than my ride with the dp) and having it stick up thru the hood..didn't notice any lack of low end either.

55* at idle means IMO something's wrong . . . LOL like major vac leak or something with the carb idle circuits . . .

I forgot which one of the mags ran an interesting article on T-Ram setups a year or two ago. They tested like 10 different T-rams setups -- a few didn't work worth a **** but one or two that actually outperformed a fully optimized single 4 bbl carb and s/p intake. They used a Speed demon carb and maybe a Vic Jr if I remember so the single carb setup was no slouch.

Anyone remember that article? I think their conclusion was that if the runner length and cross-section was right for the engine combo a T-Ram would do better than a single carb setup.

Here is a link for you to read. I could not find the main link. So it may be hard to understand. This is a carb intake combo comparison done on the same sbc back in 2002 by hot rod. http://www.hotrod.com/techarticles/60638/index5.html The other link here shows some other ones they tested under the names of carb shootout. http://www.hotrod.com/searchresults/?scope=T&sitename=hotrod&terms=carb+shootout&x=8&y=8 Take the time to read some of the other results. Please note that the tunnel ram set up made more overall "torque" and "hp" than the 4bbl and manifold set. I only point that out because everyone says that tunnel rams cost torque on the bottom end. Read it for yourselves. I had a friend that had been telling me to go to the t-ram to help out with my lack of torque vs the Victor Jr I was using. After reading this I gave it a try. I picked up mega bottom end with the t-ram in my application. Now keep in mind that I did go with the "small runner" t-ram. Enjoy Monte

has anyone compared a tunnel ram/single carb setup to a single plane/carb setup on a high rpm stroker smallblock? just curious if thats an experiment worth trying or would the tunnel ram erase the advantages offered by the longer stroke?

It seems like for an already built motor it could work well to put one on, but maybe from a ground up engine build it wouldnt be the best way to make some power. I've been slowly pricing and collecting parts for a 496 build and I was just wondering what to top this thing off with. I dont know much about EFI but the more I see it and read about it, the better it sounds. So I may be looking into that :D But tunnel rams, they should do look nice.

Actually I retract what I was thinking before. If it was a ground up build, it could be built specifically for a tunnel ram, BUT probably better ways to go?

I think in that same article Monte cites, they didn't continue with the 3X2 they were testing since it was too lean on the dyno. :(

Phil I would consider firing the motor up with a simple single 4bbl that you KNOW works OK. I don't think there is anything particular about a tunnel ram engine, just make it a bit hot is all, the usual hot street 3500-6500 powerband and the street rams (in that test Monte quotes) should rock out!

I like multi-carb setups, They work well once they're dialed in too!

Tunnel Ram... I know I am late to this thread but you are right up my alley. I have been running a tunnel ram for over 10 years on the street and strip with a M21 behind my BBC Comaro. I have a wieand tunnel ram with 2 Holley 600s with a quick change vacum secondary and a secondary metering plate that accepts the standard Holley jets.
Yes, if you aren’t familiar with carburetors you may have a hard time tuning it. But with a little research you can have the car running like a top.
I had tuning issues at first but I was able to resolve mostly all of my problems.
Here is some common problems and how I solved them.
Idling: 1st, believe it or not. I found out that tunnel rams like heat in the engine. I put in 180 degree thermostat and the engine will idle as low as 950 rpm. But my UD Roller is really radical at that RPM so I stepped it up to 1150 RPM.
2nd thing to do with the with any dual Holley carb set up. Is to lean the idle circuits. I used fine piano wire in the idle circuits. This will save you from drilling holes in the butterflies.
This will bring the responsiveness back to the idle screws and the engine won't have any idle surging problem.

Vacum: This can be low. But the cam will surely dictate that. I ran a flat tappet Lunati in it for 4 years and had about 6" of vacum at idle 1150 RPM. That’s why the vacum canister is in the picture. The power brakes still worked :D
The UD Roller I have in it now pulls 10" of vacum
at the same RPM. I change the power valves accordingly.

Fuel mileage: If I stay out of it. I have got as much as 9 MPG I guess. 4:11 gears don't help neither smile.gif

Street manners: You can't stop heads from turning from seeing those carbs coming out of the hood tongue.gif The bottom end torque may be down. But I can't tell with my BBC. It will turn my 295 mcrearys as low as 2000 RPMs.

Race: My old set up ran mid 11's, pulling the old 4 speed. I haven't took my new set up out to the track yet. I'm still putting some street miles on my new setup, since it is a street car.

And yes, it may run faster with a single carb set up. It’s just nice to be different. But if you are serious racers, yes a single carb is the way to go.
(Sorry about the image size)
http://home.nc.rr.com/everc/images/engine1.jpg

Da chevy, have you ever considered different air cleaners? I was using the 7" K&N on my set up. I kept running out of air at WOT and that was with my SBC. I went to the 9" K&N with a filter top. That cured my problem but, the air cleaners touch each other on my set up. I would think a big block would require even more air . Just a thought. Monte.

Monte, You are right, I do need to change those air filters. I am trying to find some of those triangle style air filters. But I can seem to locate them anywhere.

I ran both a small block and a big block. I had a 468 BB with two 660's on a Weiand polished tunnel ram as a daily driver (70 Chevelle) years ago. I also had a 71 Chevelle with a wild 350 and a pair of 600 Holleys on an Eldelbrock Victor Ram back in my high school days (man did the chicks dig that car!). Both looked bad ass however the 468 was a flat out a beast to drive. :eek: I sure miss those cars! tongue.gif

Last year we ran a 400 ci small block in a 68 all steel firebird. the motor had 11-1 compression, 195 AFR heads and a comp 294S cam. with a 3500 stall and 3.73 gears the car was a blast to drive. he ran a weiand street tunnel with dual 450 carbs. good luck mike