[gutlassracing]

I have a 18* degree headed 540 ci with cfe sheetmetal intake .. It has a older pro system single 1140 cfm dom on it now and I have been pondering on swapping to 2 dom's .. What will in increase hp if any and is the motor big enough to be thinking of 2 carbs ?

 

[yeti]

In relative terms, the dual-quad 409 Chevy and 427 Ford had about 1200 CFM on 425 HP. If you have 2300 CFM (1150 x 2) and your engine only makes 850 HP, you would have less carburetion (per HP) than a production engine in 1963.

 

[kingjack]

I dont think the motor is big enough unless you spinning it really hard.

 

[bad 68 chevelle]

I'm going to run 2 carbs on mine but it is a 632 with 18* heads. User onefast68 on here just went from a single to dual and he picked up alot, he also has a 632 with 18* heads, maybe he will chime in and help you out. I think you will be fine because those heads work really well.

 

[onefast68]

most say its a 40hp increase.

my experience on my 632

9.10 at 150 with a single carb intake and a 1500cfm carb
8.76 at 157 with a dart tunnel ram and 2 1200cfm pro system carbs.

was well worth it for me.

also put a lexan scoop on it,so it force feeds it with air.LOL

 

[JeffMcKC]

The fuel and air will both want to go straight,,,,,,, fuel distribution alone will help.

 

[Harper 68]

going from a 1150 prosystems single dominator too a tunnle ram and two prosystems 1050's on a 14:1 509. 2tenths 3mph in the blue chevelle. and it would rev soo much faster!

 

[Looey]

great thread!....

 

[onefast68]

oh!we gonna post pics!here is mine.the et's above was on the motor.

 

[Looey]

Sorry, I'm a pic postin' ho. Your car is bad to the bone! Love the lexan scoop. I talked to the metal.man about making one for me.

 

[Half Breed]

I had a 14 degree 540 using a profiler TR. I ran two different divisions one allowing a single carb and another allowing duals. My single was a 1600 CFM pro-systems and the duals were 1125 pro-systems. My engine picked up a little over 50hp from the switch. My engine was spinning between 8800-9200. I was running a lot back then and would sometimes change back and forth between the single and the dual three times a week!

 

[1 quick z]

Onefast68, who made your lexan scoop? Definetly interested.

 

[hellbound]

Onefast68, who made your lexan scoop? Definetly interested.

also if i can ask how is it held on ? i see no bolts ?

 

[onefast68]

info sent 1 quick z...how fast have you been on motor?

loey,your slammed tube chassis looks bad ass as well.

most people are convince 1 carb is as good as 2...i some cases its true...on bigger inch race motors i will recommend 2 carbs from now on.

hellbound...its has one bolt in the center with a bracket under the carb flanges in the center.

 

[JeffMcKC]

You see the one huge bolt in the center of the carbs?

 

[JeffMcKC]

The cross bar between the vents must have some large holes to make it so it does not cause a pressure differental between the atmosphere out side the tubes and the air in the bowls changing the fuel mixture????? Fuel is pushed because the high pressure in the bowl compaired to the low pressure in the venturi. Not dissing just asking ?

 

[onefast68]

The cross bar between the vents must have some large holes to make it so it does not cause a pressure differental between the atmosphere out side the tubes and the air in the bowls changing the fuel mixture????? Fuel is pushed because the high pressure in the bowl compaired to the low pressure in the venturi. Not dissing just asking ?

6 or 7 5/16 holes in each one...looks much better than hose with a slit in it to me.lol..been using these for many years.

 

[JeffMcKC]

Large holes I see, thanks looks cool.

 

[desoto30]

most say its a 40hp increase.

my experience on my 632

9.10 at 150 with a single carb intake and a 1500cfm carb
8.76 at 157 with a dart tunnel ram and 2 1200cfm pro system carbs.

was well worth it for me.

also put a lexan scoop on it,so it force feeds it with air.LOL

sounds like a lot more than the 40 to 50 HP always quoted, to me

 

[bad 68 chevelle]

sounds like a lot more than the 40 to 50 HP always quoted, to me

That differnce was on motor and the cam is supposed to be a nitrous cam, that thing should really fly when he makes his nitrous hit.