950 HP CARB

[BOZ-RACE]

first up i would like to say hi to everyone,what a great forum
anyway heres my first question.my mate has a 406 sbc specs are:
400sbc bored to 406ci
2 bolt mains
eagle crank 3.75 stroke
eagle Hbeam rods
flat/t pistons forged
10.8.1 comp
reed solid roller cam 288 adv dur,254@050,108lobe sep,580v/lift
world sportsman 11 200cc ported now 210cc flow 276cfm@28 @650lift
super victor port matched
750 mighty demon
1 3/4 4 into 1
DRIVELINE:
turbo 350 full man
dominator 3500 stall
ford 9inch 3.9 gears
26.10 tyres
CAR: HX holden sdn weight 3300 lbs inc driver
POWER:485HP @6100,488 FT LBS @4500 @flywheel
401HP at wheels in car, chassis dyno
best et so far 11.18@ 121 mph in street trim running 26-10 slicks
anyway we are going to try a new dyno guy and he recommends a change to a 950 HP holley,now im not so sure about this, as this is a true street car and occasional drag meets.as ive always been cautious not to over carb engines, this new guy swears it will go much better with no loss in low speed torque when tuned correctly.
sounds big to me what do you guys think,is there something im missing here?
also what do you think of the power we are making so far with this combo should it be making more if so what would you do different?cheers paul

[aedcarburetors]

im not a real fan of any carb body with no diver between primary and secondary venturii ..........HP bodies , BG , Demons and Pro Form Bodys all suffer from eddie swirl across booster ..... flow doesnt become laminear to around 4000 rpm on a small block with a 1.375" venturi.... ....earlier 4150 bodies are better with the choke horn milled to balance flow in the front and back venturies .... if you make up a centre devider plate that slips over the air cleaner stud boss on a HP or Pro Form or BG body u will pick up 5-10 foot pounds in the mid range ....... as yours in a street driven thing .... id always recoment the earlier bodys .......the same goes for dominator bodys ....its eddie swirl from adjacent venturri at lower RPM or during a gear change that unsettles flow down through the booster ....... this is why guys like Phil Brassure make tops for dominators with extended rams tubes up from the apex of venturii.... they dont make anymore top end power but they will recover from a gear change much quicker .........

950HP doesnt flow anywhere near u think it does.... its got the same venturi size 1.375 as a 750DP or 750 Demon... there for signal to the main well is the same .... its just got the bigger 1 3/4 base which will help it in the top end .... u might find u will MPH slightly more .. but will ET about the same ......

[67RS502]

AED
Are you saying to make a plate, which sticks straight up, that separates the primary
venturis from the secondary. How high should it be? I'd like to try this on my Proform 950
on my 383, which will see the track soon.
Thanks
Rafel

[Doug Schriefer]

Boz,

With the torque converter you're running going to a larger carburetor will most likely hurt your throttle response, and acceleration down low especially while driving on the street. A larger carburetor will give you a little more top end, and depending on your traction situation may help your ET a touch but will sacrifice drivability.

[mstngjoe]

I too would like to say thanks to Speed Talk for this forum and all the great information that is provided by the members.

I've been lurking for a little while and this is my first post which was prompted by this:

.........
950HP doesnt flow anywhere near u think it does.... its got the same venturi size 1.375 as a 750DP or 750 Demon... its just got the bigger 1 3/4 base which will help it in the top end .... u might find u will MPH slightly more .. but will ET about the same ......

I have a similar statement posted elsewhere. I was very curious to find out more information about how this conclusion was reached.

But my questions were never answered relative to the basis of the claim other than some internet "sales" links. No flow test results were ever posted.

I'll pose my question to aedcarburetors. May we assume you are affiliated with AED?

I'm curious as to the testing equipment and method used to determine that the "950HP doesnt flow anywhere near u think it does."

And what exactly did the Holley 950HP flow in your testing?

I realize there is more to carb performance than solely the cfm rating/flow, but the cfm rating is obviously what you are disputing.

I'm under the impression that all 4 barrel carbs are rated at 1.5" of mercury drop (20.3" water).

I can understand some variations due to test equipment, method and operator, but you seem to imply the 950 flows significantly less than it's name.

I appreciate your time in helping me to learn.

[Doug Schriefer]

Holley 950 HP.

Holley rated the 950 HP differently than the other carburetors in an attempt to go after the carburetor modifiers that increased air flow. A 950 HP is what the modifiers would commonly refer to as a "Big Base" 750. They have the same venturi area as a 750 carburetor with the larger butterflies or baseplate of an 850 carburetor. This means it is physically a smaller carburetor, and more restrictive than an 850 Holley.

[mstngjoe]

Holley 950 HP.

Holley rated the 950 HP differently than the other carburetors ......

Do you know at what pressure drop they are rated?

[Doug Schriefer]

Holley 950 HP.

Holley rated the 950 HP differently than the other carburetors ......

Do you know at what pressure drop they are rated?

That you'd need to get from Holley.

[mstngjoe]

Okay.......well, I suppose I could ask them. I'm not to confident I'd get an answer, but I'll try.

Meantime, at what pressure did BG test the 950HP?

[mstngjoe]

BTW.....BOZ-RACE...sorry for the hi-jack.

[Doug Schriefer]

Okay.......well, I suppose I could ask them. I'm not to confident I'd get an answer, but I'll try.

Meantime, at what pressure did BG test the 950HP?

Back when we were doing Holley carburetors we were dry flow testing, so the numbers are not comparable.

What I can tell is that our 825 carburetors which have a better air entry, and larger venturi (same size butterfly) Will flow 980 CFM @ 1.5" Hg at 12.5:1 A/F

[aedcarburetors]

std 950 HP body Flows 812cfm wet at 12.8:1 corrected at 25in H2o on AED's bench in Virginia ...................make the divider plate the same height as the body as it blends down from the aircleaner rail

[melsie68]

Holley 950 HP.

Holley rated the 950 HP differently than the other carburetors in an attempt to go after the carburetor modifiers that increased air flow. A 950 HP is what the modifiers would commonly refer to as a "Big Base" 750. They have the same venturi area as a 750 carburetor with the larger butterflies or baseplate of an 850 carburetor. This means it is physically a smaller carburetor, and more restrictive than an 850 Holley.

Okay, what about the 4150 Holley 1000cfm HP Series carb? I have never measured anything on one so I cannot give dimensions, but if you look down the barrels of these carbs they appear to be much larger from top to bottom...?

[Doug Schriefer]

Holley 950 HP.

Holley rated the 950 HP differently than the other carburetors in an attempt to go after the carburetor modifiers that increased air flow. A 950 HP is what the modifiers would commonly refer to as a "Big Base" 750. They have the same venturi area as a 750 carburetor with the larger butterflies or baseplate of an 850 carburetor. This means it is physically a smaller carburetor, and more restrictive than an 850 Holley.

Okay, what about the 4150 Holley 1000cfm HP Series carb? I have never measured anything on one so I cannot give dimensions, but if you look down the barrels of these carbs they appear to be much larger from top to bottom...?

The 1000 HP has the same physical dimensions as a 4781 850.

[BOZ-RACE]

no probs mstngjoe its all the same type of info im chasing also,keep it coming guys im learning some good stuff on this subject cheers boz. so what would be the advantage of going the 950 hp over a 850 if the 950 is more restrictive wouldnt a tricked 750 or 850 be better.