What combo was that Dominator/tunnel ram sitting on, and in what type of ride?  

I have a small cubed, tunnel rammed motor.  Its a 289. (allegedly a 306 as per the guy I bought it from, if it is or not, I don't know).  Anyway, I run two holley 450's which are single feed (non double pumper) with mechanical secondaries.  They are cheap, I paid $187.50 apiece for them brand new from summit maybe a year or so ago.  I plugged the power valves which seemed to help the off idle stumble a bit, otherwise they work okay.  My linkage is ultra redneck, but that is another story.  

Throw on some velocity stacks, and the head turning factor flys through the roof.

68 Camaro that was on the News 2003, it will be at LACR today for the street race event today. The manfold was warped during a nitrous explosion and has not been fixed yet, so it is running a single plain w/dominator carb.

http://community.webshots.com/album/548102192wtqhzd

I plugged the power valves which seemed to help the off idle stumble a bit, otherwise they work okay.

Try a 50cc pump on both carbs and see if that takes care of your stumble.

The reason that I didnt do that was because I figured that I would have more than enough pump shot because of the 2nd carb.  If I went to a 50cc pump, I would then have a total of 100cc's.  I figured that my problem was too much gas if anything.  

good thought though.

I ran 2 50cc pumps on a double pumper. The motor had issues and this bandaided it for a while. (blown head gasket) When I have delt with a vac sec carb with a 2" spacer and a light sec spring, I would have a stumble. The 50 cc cured it. They make a 30 cc also and your standard 25 cc.  

OK:

first off:i love tunnel rams on the street also-kudos on the persistence and all the hard work.

how did you set up the secondary side metering?go with AED or QUICKFUEL TECHNOLOGIES secondary metering plates.these allow you to use screw in jets to taylor secondary side fuel curve.you also do not need to change hardware or transfer tube.try a brown spring for secondaries-tie in you vacuum source.keep a 28 shooter and try  to lengthen pump shot (red cam?iirc).

keep as much initial timing in it as possible.3.08s and the short tire isn't TOO bad..but IMHO-go to 2600 stall and 3.42s.

keep up posted.

NOSNERD

Hey EKF I thought 30cc was standard on a double pumper. I'd have to ckeck, but I'm sure I'm right.  

Hey EKF I thought 30cc was standard on a double pumper. I'd have to ckeck, but I'm sure I'm right

You maybe right, I don't see any replacement diaphram for a 25cc. On early carbs they look smaller then the newer carbs, but I thought they were 25cc.

We ran the tunnel ram carbs and all the tunnel ram carbs listed run 50cc pumps-

List 4224 = 660 cfm 2x4 inline 1:1 linkage w/50cc pumps, 

List 9375 = 1050 cfm 2x4 soft progressive linkage w/50cc pumps (when we ran these they were list 6464 and had 1:1 linkage and dual 50cc pumps = 100 cc per carb, 200 cc total on a dual Dominator tunnel rammed SBC, looked bitchen but it was 1 mile an hour slower than the 660's, small price to pay for an intimidating look)

and when we ran 750's on a tunnel rammed SBC we put 50 cc on the front and left the 30's on the rear,

also when we ran 850's on a tunnel rammed BBC we ran 50cc on the front and 30's on the rear. The 850's came w/30cc fronts and 50cc rears so all we did was reverse them.

I also feel that the two 450's that Nanders has on his 289 are to small. I've always been told that if a motor uses a 650cfm carb in a single carb application that in a dual carb application you still use the 650cfm carbs, it's just that you use two of them. I've had a couple of buddies that have ran 289's in old mustangs and they all ran 650cfm holleys. I think where some people get confused is they think since they are running two 450cfm carbs that now they have 900cfm, which is not the case.  

I also feel that the two 450's that Nanders has on his 289 are to small. I've always been told that if a motor uses a 650cfm carb in a single carb application that in a dual carb application you still use the 650cfm carbs, it's just that you use two of them. I've had a couple of buddies that have ran 289's in old mustangs and they all ran 650cfm holleys. I think where some people get confused is they think since they are running two 450cfm carbs that now they have 900cfm, which is not the case.

I think there is some truth to that, for us 750's work great on a tunnel ram as they do on a single four in a SBC and 850's work great on a BBC tunnel rammed or single carbed. We ran dual dominators on a SBC with good results, all we did was lean out the idle circuit to make them work on a tunnel ram or single four manifold, and dual dominators work really good on a tunnel rammed BBC as it does on a single four barrel BBC.

one way we use to tune a tunnel ram was to dial the carbs on a single plain manifold one at a time and then put them on the tunnel ram to get a starting point. The other way was to set it up as they came new from holley to get a starting point to dialing the carbs in. The first way got us a closer starting point but required a manifold change or another running motor. With a manifold change it gave us a base line on how much the tunnel ram improved the performance over a single four at the track.  

Why wouldnt two 450's give you 900 cfm?  You are adding twice the amount of airflow potential.  I could put a septum down the center of of my upper plenum and in effect have one 450 carb feeding the front four cylinders, then the other 450 feeding the back 4 cylinders for a total of 900 cfm.

I don't understant how that couldnt be true?

Although, if you have seen that running carbs about the size that would be required for a single carb set up, then I am curious as to why that is?  It doesnt sound at all logical.

You have to realize that the carbs flow 450cfm, and just because your running two of them isn't going to change that. It might not seem logical but that is the way it is. Put it this way if your running a single carb or a dual carbs your still only filling one cylinder at a time, so ask yourself would you run a 450cfm carb on your motor in a single carb application, most likely not. The same goes for a dual carb setup, basically with the dual carb setup each carb is supplying fuel to 4 cylinders but realize that your only supplying 450 cfm to each cylinder where as with a single carb application where you'd run a 650cfm carb your supplying 650 cfm to each cylinder. This probably isn't the best explanation  but you should get the idea.  

I understand what you are saying, But the twin carbs give you twice the throttle bore for your single cylinder to pull from.  Also remember that when a cylinder wants to gulp some mixture, it is going to pull a vaccum, which will find its way to both carbs.  (common plenum)

Even without the common plenum and using the front and rear four idea, you will still see that the demand on the carb is cut in half, and therefore could get away with a smaller carb.  

You do bring up some interesting points.

Thou shalt make it fast while keeping it loud, and thou shalt make plumes of tire smoke as a burnt offering to the Lord God.  As these things are pleasing to him

-Nanders 4:11