Actual cfm used vs carb size

[F-BIRD'88]

Put the 2 carbs (can be 2 dominators if ya got em) on a 2x4 to single 4bbl adapter, bolted onto your single 4 bbl racing intake and test compare to the 1 single carb.
It will make more power and go a bit faster.
Then put them on a tunnel ram, faster yet.
2 carbs is better.

A decent 2x4 carb adapter will add about 2.5" to 3.5" to the final carb height.. But will still be a bit shorter over all than a tunnel ram.

It is easy and low cost to optimize the final height that works best for you, using carb spacers. Can be under the adapter or under the carbs, on the adapter.
Testing will show whats best.

[cjperformance]

^^ i would actually bet that it would not go faster. I would not dispute that it may make more power but its not going to shift recover and ET faster.

[Steve.k]

I have a tough time with this topic. Every single time I've added bigger carbs the cars picked up. From a single 830 to 1050 dommy was huge on a single plane strip dommy intake. Im going to try the 4150 style quickfuel 1050's cause i have them and see which way it goes. Even in the burn out box with the dual dommies the car revs up way quicker. However never tried the tunnel with single carb as no top fits ur19.

[randy331]

^^ i would actually bet that it would not go faster. I would not dispute that it may make more power but its not going to shift recover and ET faster.

I'd bet the 2 carb to single set up won't make more power on a dyno either.
Once you have been around a dyno for awhile, you start to realize there is no magic.

Randy

[Steve.k]

A friend just finishing a 460 cube sbc that had dual 950's. It dynoed just short of 1000hp and going in rail. He's switching the dual carbs for a big single as he says the rail will et quicker despite quite abit less hp.

[andyf]

That could be true. There is a difference between making peak power on a dyno and getting a car to run down the track. Sometimes more peak power makes the car faster, sometimes it doesn't help. You don't need dual Dominator carbs on your engine since you're only making 700 hp but if you have them and like them then keep them.

[ClassAct]

A friend just finishing a 460 cube sbc that had dual 950's. It dynoed just short of 1000hp and going in rail. He's switching the dual carbs for a big single as he says the rail will et quicker despite quite abit less hp.

If it makes more power on the dyno and goes slower in the car, that's a chassis tune up issue, not a dyno issue. I've watched people destroy engines that didn't run what the dyno said it should becaseu they are either too arrogant or too stupid (or both) to fix the car.

The usual suspects are wrong converter (not always stall speed) not enough gear (it's simple math) and the suspension hasn't been serviced since Ronald Reagan was in office.

A tunnel ram and TWO carbs is always better.

[CGT]

A friend just finishing a 460 cube sbc that had dual 950's. It dynoed just short of 1000hp and going in rail. He's switching the dual carbs for a big single as he says the rail will et quicker despite quite abit less hp.

In something that accelerates as fast as a 1000hp in a rail does, fuel distribution under that force could be a reason for power on the dyno not showing up at the track.

[ClassAct]

A friend just finishing a 460 cube sbc that had dual 950's. It dynoed just short of 1000hp and going in rail. He's switching the dual carbs for a big single as he says the rail will et quicker despite quite abit less hp.

In something that accelerates as fast as a 1000hp in a rail does, fuel distribution under that force could be a reason for power on the dyno not showing up at the track.

Pro Stock was in the .980ish 60 foot times before they killed the class with EFI. So acceleration has nothing to do with it.

[Steve.k]

All interesting info guys! I will say the car picked up 3/100 on 60ft and .18 in 1/8 from adding carb and ram. Its hitting the tire alot harder and was crushing tire bad. Will play with that this summmer to shoot out gate a little harder.

[F-BIRD'88]

A tunnel ram with a single carb will be very hard to tune right and will et and mph slower than 2 carbs.
2 carbs is better.

On the cool UR19 clevland TR you'd be much better off dialing in the plenum (height volume etc) for the carbs.

[F-BIRD'88]

But a big racey single carb intake will work very well with 2 x4 carbs on it. Next best thingy if no tunnel ram available. Or you just want dual carbs. 'cause....

Really lets you max out the roots street blowers with a single 4bbl carb flange.

[PackardV8]

A tunnel ram with a single carb will be very hard to tune right and will et and mph slower than 2 carbs.
2 carbs is better.

Just trying to learn something here, as I always found two carbs more difficult to tune, but those also had to be streetable. What are the factors which make the single carb tunnel ram difficult and slow?

[F-BIRD'88]

A tunnel ram with a single carb will be very hard to tune right and will et and mph slower than 2 carbs.
2 carbs is better.

Just trying to learn something here, as I always found two carbs more difficult to tune, but those also had to be streetable. What are the factors which make the single carb tunnel ram difficult and slow?

. Bad bad fuel distribution. End cylinders too far away with 1 carb.


On dual quads and tunnel rams the edelbrock carbs are very easy to tune in. Recomend the recent 650 AVS2 carbs.
(Anything street/strip, )(bracket racer friendly)
Apparently there is hint of a 800 cfm version AVS2 in the works.

[cjperformance]

^^ i would actually bet that it would not go faster. I would not dispute that it may make more power but its not going to shift recover and ET faster.

I'd bet the 2 carb to single set up won't make more power on a dyno either.
Once you have been around a dyno for awhile, you start to realize there is no magic.

Randy

I agree! Hence i said 'may' ,, i felt bad saying it not go faster , so i felt compelled to add a softener