Actual cfm used vs carb size

[Steve.k]

Now that all makes sense Mark! So the tunnel ram which essentially gives a straight or alot straighter shot into head helping with fuel distribution. Then the 1050 offers less pumping losses as compared to smaller diameter carbs. While the engine may not use the 2100 cfm, it does allow it to fill engine better. The smaller 650's may offer better atomization for fuel distribution so the 1800 dollar question is will the atomization gains offset the gains from pumping losses in dommies.

[PackardV8]

How do you guys determine your carb size for specific build?

Above THE SPECIFIc BUILD and SPECIFC USE seem missing in the original post and most replies. How can a carburetor recommendation make sense without that information?

Regularly street driven in all weather? If so how many would recommend two 1050 Dominators?

Strictly strip? If so, cold starts, idle and fuel mileage isn't an issue.

Dyno racing? Just hero top end horsepower or area under the curve?

All the above and in between have requirements which will move the carburetor recommendation.

jack vines

[Steve.k]

Drag car only. Full body and heavy 3700 lbs. 438 cubes 4.05x4.25 chi 4v heads 370@.800 and 255exh @.800. 13.5 racetecs and ur19 edelbrock tunnel ram dual 6464 1050. Crane roller .728 on both 262-272 @.050. 1.73 rocker. Roller c6 with 5600 convertor and 5.14 gear on 28x10.5 Mickey. Above combo 703@6700.

[Steve.k]

If smaller carbs net some gains in et I'll put on. However when i had single dommy every one said it was way to big. So holley spec'd the 830. Not only was it slower on track it netted 22hp less on dyno. So not sure what to think of 650 dual setup.

[swampbuggy]

Steve...it would be interesting to try a pair of 950's Mark H.

[Steve.k]

Yes Mark it would be. Im open to anything that will gain. I know a buddy of mine went with dual 950's on a sbc chevy 450 cubes and it fed 1000hp so feed mine easy. I have two quickfuel 1050's that are 4150 carbs i could try.

[swampbuggy]

I would try them for sure Mark H.

[prairiehotrodder]

i went from a single 1050 on a super victor to a pair of 750 track warrior carbs and gained .2 in the quarter. A pair of 1050 dominators would likely gain a few more hp but it costs to much to find out. I asked lots of respected carb shops which carbs they would suggest to put on my tunnel ram before i bought the 750's. They all said 750's or 1050's. There was no in between. Not sure why. Seems 850's and 950's are not suitable tunnel ram carbs ???
i'm happy with what i have. thats my experience. If i had a free chance to try some 1050's i would but thats not likely to happen.
Brian

[Steve.k]

Yes it's possible!! You travel out to Rimbey Alberta 1/8 track and I'll swap you. Ill try yours and you try these 1050's.Ill even cover your entry fee for a weekend. Its the smoothest track in western canada so you will enjoy it.https://m.facebook.com/caraceways/?__no ... 68%2F&_rdr. Check it here. Im in charge of drag strip side.

[prairiehotrodder]

Wow ,i even built a motor (BBF) for a guy near Rimbey. To bad my intake is not a dominator flange. Would be a fun test. Maybe you should come to SIR in Saskatoon.

[Steve.k]

Yes been hoping to get to sask. soon just cant seem to get outta here. Who you build for. I know most the ford guys around here.fwiw i have the spacers to fit.

[Tom Walker]

Jmarkaudio, very good write up and seems to explain what is actually happening with the different carb combinations. Thank you.

[cjperformance]

^^ fabulous post Mark

[jmarkaudio]

With two carbs the difference from smaller to larger carbs will be less. The change in pumping losses will be small at best, so it comes down to which provides the most homogenous mix, distributes the best, and burns most consistent. RPM will come in to play, the demand from a 500" engine at 7500 will not be the same as one running 11,000...

[andyf]

How do you guys determine your carb size for specific build? I currently run two 1050's on 438 cubes that netted 51hp gain over a single 1050 at exactly the same rpm. When talking to holley they recommended two 650 built carbs as they said engine can pump 715 cfm. They were close as single carb used 740. Thoughts??

Holley is correct that your engine isn't using anything close to 2100 cfm so you don't need twin 1050 carbs. The switch to a tunnel ram was probably why you picked up 50 hp, not the dual Dominator carbs. My guess is that your car would work best with dual 650 or 750 size carbs. I'm not so sure that the actual size of the carb matters as much as the signal strength. There are carbs that work and carbs that don't work and usually it is impossible to see the difference. The good news is that you should be able to sell the twin Dominators for some decent money. Another option would be to added skirted boosters to the Dominators and turn them into 750's. That might be worth an experiment.