Which carburetor for BB??

[CudaCraig]

Yes , the 4150 doesn't have removable bleeds generally , the Ultra should be far more adjustable

You mentioned ProForm, would you consider the Holley Ultra HP and ProForm Race series to be equal?  Same adjustability?

[brads70]

What other carbs have you owned?  Just trying to get a feel for how it stacks up.

What brand AF ratio gauge did you use?  Do you use it only at idle or were you able to utilize it under load, like on a dyno?

I've had various Holley's, demon, stock carbs, etc....
I just used a autometer A/F gauge. I leave it hooked up all the time, so yes you can use it under load, cruising etc...
I believe QF and proform are the same company just divisions of.
My carb says both on it.

[Chryco Psycho]

I have worked with virtually every type of carb , Carter AFB, AVS, TQ , Eddy AFB & AVS , Holley production 4160 , 4150 , older series & brand new HP series , 6 packs , 2300 series ,  Avenger series , Dominators , QF , Demon , Proform , & even EFI
 my favorite is -
#1 - EFI
2- Proform & QF
3-Holley HP

[CudaCraig]

I have worked with virtually every type of carb , Carter AFB, AVS, TQ , Eddy AFB & AVS , Holley production 4160 , 4150 , older series & brand new HP series , 6 packs , 2300 series ,  Avenger series , Dominators , QF , Demon , Proform , & even EFI
 my favorite is -
#1 - EFI
2- Proform & QF
3-Holley HP

  What EFI systems do you like?  Is EFI something I should be considering for my car or is a good ol' carb still the best route for what I plan to use it for? 

[Chryco Psycho]

Nothing works as well as EFI carbs are just a gas leak !!
 the problem is you can get the best carb for under $1k but EFI will run closer to $4k
 I build my own system , using components from various Mfg , The Computer I sourced from SDSEFI in Calgary [http://www.sdsefi.com/], it is awesome , you have a small handheld programmer , you can control everything , timing can be adjusted every 250 rpm , same with jetting , powervalve & accelerator functions from 500 rpm to 10k rpm , the choke function is controlled the same way with a different value every 3-4* C in water temp . everything a carb can do can be adjusted far more accurately at any rpm . When using Race cams & making very low vacuum the engine will still sound stock & idle perfectly as the exact correct amount of fuel is delivered & better atomized right behind the valve so every cylinder fires every time .!

[CudaCraig]

I have worked with virtually every type of carb , Carter AFB, AVS, TQ , Eddy AFB & AVS , Holley production 4160 , 4150 , older series & brand new HP series , 6 packs , 2300 series ,  Avenger series , Dominators , QF , Demon , Proform , & even EFI
 my favorite is -
#1 - EFI
2- Proform & QF
3-Holley HP

What about the Holley Dominator vs the Holley HP?  Any advantage to a progressive mech secondary?

[CudaCraig]

Earlier on in this thread it was mentioned I need 950 cfm. When I use the online cfm calculators they state 828 cfm needed at 100% VE and only a little over 700 cfm for 83%VE.   The performance shop nearby says I only need a 750. It doesn't seem like enough for 477 cu in. I want it to be fed adequately, but not drowned it out. Thoughts?

[dodj]

I also vote for Quick Fuel.
I picked up one of the Black Diamond carbs and am very happy with it. I have it on a  440, not a 477.
http://www.quickfueltechnology.com/carburetors-black-diamond-series/black-diamond-ss-series-1.html

[cudabob496]

the 850 Holley DP with annular boosters makes all the power I need
for my 496. I should be over 600 hp.

[Strawdawg]

Earlier on in this thread it was mentioned I need 950 cfm. When I use the online cfm calculators they state 828 cfm needed at 100% VE and only a little over 700 cfm for 83%VE.   The performance shop nearby says I only need a 750. It doesn't seem like enough for 477 cu in. I want it to be fed adequately, but not drowned it out. Thoughts?

the online calculator has a number of flaws in it and does not give an accurate assessment.

For all out performance, 950 cfm would be a good choice.  If this is basically a street car, then an 850 cfm will be adequate.  Quickfuel/Proform give the most bang for the buck.  The new Holley Ultra HP is a good carb to for a bit more money.  I doubt that any of the three will produce measurably more power than the other two.

[Chryco Psycho]

The Dominators are excellent carbs also but compared to a brand new Proform I doubt there would be a significant advantage , I think Holly has Ultra series dominators though , the technology is always improving !!
I used a EFI system I cobbled together buying the best parts from different sources & it was excellent , I used a computer system From SDSEFI , while it is not self tuning it came with a hand held programmer to adjust everything , no laptop needed , I used an Accufab T body as it was 1200 CFM & & only 1.75" tall , approx. 1/2 the height of a carb so it allowed room for a larger air cleaner .
 I am not sure why the formula doesn't work but I believe because the carbs are flowed with higher vacuum than the engine will make at WOT the rating is too high so a 750 might flow 750 at 1.5 " it won't at .5" , my formula is 2x the CI so 500ci would be 1000 cfm drop to the nearest carb & a 950 will work well , a 750 works great very responsive just like a 2 bbl , but from max power 950 + is where you need to be , why spend all the $$ to build the most powerful engine combo & limit it with a small carb ?

[Strawdawg]

 I am not sure why the formula doesn't work but I believe because the carbs are flowed with higher vacuum than the engine will make at WOT the rating is too high so a 750 might flow 750 at 1.5 " it won't at .5" , my formula is 2x the CI so 500ci would be 1000 cfm drop to the nearest carb & a 950 will work well , a 750 works great very responsive just like a 2 bbl , but from max power 950 + is where you need to be , why spend all the $$ to build the most powerful engine combo & limit it with a small carb ?

that is one of the two major reasons that the formula fails to provide the optimum sizing.

The carb is rated, for a four barrel, at 1.5 inches of vacuum whereas the old rule of thumb for a street car that we used to use was that one should see no more than 1.0 inches of vacuum on the gauge at the finish line and for a strip car, we aimed for 0.5 " of vacuum at the line.  This means that a carb rated at 850 cm would only be supplying something like 700 cfm and the engine would be begging for more air.

The second major reason that I am aware of is that the books all suggest that the car will be operating at less than 100% VE and this factors down carb size in the formula but a car with a good cam and good heads will actually operate above 100% VE...maybe 110% which gives a larger size.

Then there are a couple of other reasons that may not be as significant.

The formula is for dry air flow but with a carb, we are using a "wet" manifold and the formula does not account for this in sizing.

And the other reason, is that on a high-winding engine with good heads, mixture velocity can get too high and too small a carb will create a velocity such that fuel particles will separate from the mixture and cause a/f to lean out on the top end.  this usually affects some cylinders more than others and even a tall spacer will not cure the problem.  This usually shows up on really serious engines and not street driven cars.

I think your 2x number is about as good as it can get for most street cars.  The factory never had a problem with it and they pay their engineers pretty well.

The only downside to a big carb is that it usually takes a little tuning to optimize it for the street but even Dominators can be dialed in for a street car with patience.  Modern carbs are much easier to tweak because of the screw in bleeds, etc.

[cudabob496]

I have worked with virtually every type of carb , Carter AFB, AVS, TQ , Eddy AFB & AVS , Holley production 4160 , 4150 , older series & brand new HP series , 6 packs , 2300 series ,  Avenger series , Dominators , QF , Demon , Proform , & even EFI
 my favorite is -
#1 - EFI
2- Proform & QF
3-Holley HP

Which EFI for an engine over 600 hp?

[Chryco Psycho]

The cobbled system I used made 700+ HP on the dyno on a 440 not stroked
 You just need a big enough T body & injectors to flow the fuel

[gafletch]

Neal, I'm looking into a Proform 850. Is the street series good for 90% street use? Greg