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Discussion Starter #1
just wonder what the gains are from mild to wild engines. i have a mild 460 combo with a 750 holley 3310 and was thinking of switching to a 950 later. just wanting to see real life gains. Thanks !
 

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How "mild" are we talking? A 385 will normally benefit from more carb. Everybody said I was crazy when I changed from a 780 to a 1050 dom. "It'll never run, too much carb for a 429!" Then came the next race, they didn't talk "crap" anymore. A lot of dominators and intakes were purchased in a hurry.
 

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The 950HP is a fantastic all around carb. It flows similar to an 850DP but has the venturi of a 750 which gives it much better throttle response (compared to an 850). My 950HP has great street manners on my 472. Much better than the POS 830 annular I had on there before. The secondaries don't come in until you reach 1/2 throttle or beyond I'd guess. So, it's easy to control the power.
 

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I tried a 750 one race and it lacked power and kind of flattened out at the end of the track. I bolted on my 950 prosystems carb and it felt like I added 200 hp to the engine.
 

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12.920 with tuned 750 dp with proform main body, 12.082's with QFT 950 constistantly no other changes. Motor was 9.5:1 466 with DOVE's with 2.245/1.8 valves and comp294S with tired valvesprings and Stealth intake. The motor was my street bracket motor for 7 years in my mustang that ran [email protected] spinning for first 100ft. Had over 500 passes on it.
 

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Discussion Starter #6
12.920 with tuned 750 dp with proform main body, 12.082's with QFT 950 constistantly no other changes. Motor was 9.5:1 466 with DOVE's with 2.245/1.8 valves and comp294S with tired valvesprings and Stealth intake. The motor was my street bracket motor for 7 years in my mustang that ran [email protected] spinning for first 100ft. Had over 500 passes on it.
How much mph did it pick up switching carbs ?
 

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my little 466 was dyno'd with a 1050 dommy and and 1150 dommy. It ran best with the 1150 with 99 front and .130 rear jets. It takes every bit of fuel I can give it and it's still a little lean in the middle/top end according to the dyno sheets!
 

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Discussion Starter #9

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Go big

I have a 694 race motor with 2 950s on and tried 2 1250s, gained 80 rwhp at the chassis dyno.

I have heard if you put a vaccum port below the carb and do a wide open run that you should not pull more than 1 . If more the carb is too small and loosing potential power.

No pro here, maybe somebody else can chime it to correct.

Good luck
 

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Discussion Starter #11
wow, guys when i'm able to start making wide open tuning passes i'll put my vac gauge on it and check to see if there is any when i run it ! i just checked on a carb calculator and it said 750cfm for street use 850cfm nominal and 950cfm for racing ! i'm only going to twist it about 6000 rpm unless it wants more.
 

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That is the same thing I have been told, is that when you are at wide open throttle it should be pulling less that 1" of vaccum.
 

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wow, guys when i'm able to start making wide open tuning passes i'll put my vac gauge on it and check to see if there is any when i run it ! i just checked on a carb calculator and it said 750cfm for street use 850cfm nominal and 950cfm for racing ! i'm only going to twist it about 6000 rpm unless it wants more.
As you can see now, those calculators are crap! Experience gives the best info. Our Fords like bigger carbs than most other brands anyway.
 

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Those calculations are not crap they are intended to give you a carburetor that's sized to give about 1.5 inches of Hg at max RPM for a 4 barrel and 3 inches for a 2 barrel. The reason for this is because it virtually guarantees that the carburetor will perform well under all operating conditions not just WOT.

Making the carburetor smaller will slow you down less than you might think.
 

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Those calculations are not crap they are intended to give you a carburetor that's sized to give about 1.5 inches of Hg at max RPM for a 4 barrel and 3 inches for a 2 barrel. The reason for this is because it virtually guarantees that the carburetor will perform well under all operating conditions not just WOT.

Making the carburetor smaller will slow you down less than you might think.
I agree with Dave. The problem with most of the carb calculators is they are assuming ~80%ve and some of todays intakes are close to 100%ve. If you imput the correct ve(volumetric efficiancy) then you will be very close to perfect size assuming all other info is correct.
 
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