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How would you address the emulsification issue? Would you go down one size across the board or can you change one or two at a time?
 

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Interesting that Holley North America tells you to NOT touch the air bleeds, but Quick Fuel Australia encourages it. Go figure. I will say… that without a through understanding (and a lot of hands-on R&D) of emulsion circuits, Holley is probably right in discouraging the average grease monkey from doing that.
Kind of like the Remington 700 Triggers, they are actually great units but very easy to mis-adjust. so remington said explicitly; don't adjust them. Ended up costing Remington millions in claims paying the idiots who made them unsafe and hurt themselves or someone else.
 

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Hello,

I am a new owner of a 65 fastback 5 speed. The car came with a 850 DP Holley and has trouble running below 3000 rpm. The engine is a 347 with Edlebrock E-Street heads and a moderate cam ( I don't know the cam specs ). I am trying to figure out a good carburetor to buy for my car. I am looking at the QFT SS-650-AN. My questions is, is it enough carb to perform well at the topend? Any other carb I consider? I have some experience building and tuning megasquirt for my miata, this is my first carb vehicle.
 

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1965 Mustang GT. 11.898 @ 113.646, all motor, three pedals
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Discussion Starter · #205 · (Edited)
I am looking at the QFT SS-650-AN. My questions is, is it enough carb to perform well at the topend? Any other carb I consider?
With a ‘moderate cam’ and those heads, that annular 650 is a great choice. As to ‘others to consider’, manual transmission/light car/stroker torque gives you a lot of options. Just know that about anything will take some work on your end to dial it in. I’ll post more later.

Congrats on the Mustang 👍
 

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With a ‘moderate cam’ and those heads, that annular 650 is a great choice. As to ‘others to consider’, manual transmission/light car/stroker torque gives you a lot of options. Just know that about anything will take some work on your end to dial it in. I’ll post more later.

Congrats on the Mustang 👍
Thanks ArizonaGT. I realize that I will have to put some work into tuning the carburetor and I am looking forward to it. I need to find my spare wideband and install it in the car. The engine builder recommended a Holley 0-76750BK and some friends building a 302 for his Jaguar is looking at the new Edlebrock VRS 1450.
 

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1965 Mustang GT. 11.898 @ 113.646, all motor, three pedals
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Discussion Starter · #209 ·
I haven't. Is there some idiots smart consumer’s guide to the different types/models of carb? Holley's website it not very useful.
That’s what we‘re for 👍
Brawler is the economy/entry-level line, they’re pretty good carburetors for the money. They will have fewer bells ‘n whistles compared to the XP and HP branded Holleys, but for most street cars they‘re a good value. Same for the Quick Fuel HR (hotrod) line; not as many features as the high end stuff but they are a good value for 99% of street motors. Proform also makes some good stuff for the money.

It pretty much depends on how deep you want to dive in. Most street motors are perfectly happy with little more than typical carb adjustments and maybe some re-jetting (for your altitude and weather), but if you want infinite tuning and calibration, entry level isn’t for you.
 

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That’s what we‘re for 👍
Brawler is the economy/entry-level line, they’re pretty good carburetors for the money. They will have fewer bells ‘n whistles compared to the XP and HP branded Holleys, but for most street cars they‘re a good value. Same for the Quick Fuel HR (hotrod) line; not as many features as the high end stuff but they are a good value for 99% of street motors. Proform also makes some good stuff for the money.

It pretty much depends on how deep you want to dive in. Most street motors are perfectly happy with little more than typical carb adjustments and maybe some re-jetting (for your altitude and weather), but if you want infinite tuning and calibration, entry level isn’t for you.
I don't mind spending a little bit more initially and getting a carb with a lot more tuning features. My current carb seems to have the butterflies quite a bit open to idle. The tuning articles that I've been reading say that's a big no-no. So, I think I might be helped with a carb having idle air bypass.

Here is a picture of the butterflies on the current carb.

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Is there a chance someone here is willing to sell me a Holley Ultra XP 650?
 

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1965 Mustang GT. 11.898 @ 113.646, all motor, three pedals
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Discussion Starter · #213 ·
I am seeing a 750 cfm Ultra XP refurb on sale for ~$700. Is a 750 too much carb for my engine?
Not at all. 850 is kinda pushing it, but that’s kinda what I do 😜


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Just know that 750 Ultra will probably be calibrated rich for your heads/cam/displacement.
 

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1965 Mustang GT. 11.898 @ 113.646, all motor, three pedals
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Discussion Starter · #214 ·
Idle air bypass is a nice feature for sure, just don’t get carried away. Once you start opening the valve (by turning the valve counter-clockwise) you’ll begin to hear ‘hissing’… that’s a good indicator that you’re bypassing air. A little bit goes a long way, and it is not a fix-all. When used properly in conjunction with the rest of the tune/calibration it is a very useful tuning tool.
 

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Here in Alabama we just can't show off like that . Get e'm all lined up then,
Come back in a day or so and the dirt daubers will have every cavity in those thing full of mud .
And if you think they will be safe stored in a cabinet ,better make sure all the openings in the cabinet are sealed. Because those things ain't afraid of the dark .
Just store them in the living room like everyone else. ;)
 
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Not at all. 850 is kinda pushing it, but that’s kinda what I do


View attachment 865755


Just know that 750 Ultra will probably be calibrated rich for your heads/cam/displacement.
Your setup looks pretty. I want to put a fuel filter in line, in case there is crud in the tank. Do you put one before or after the fuel pump?

What all should I get to tune the carb?
Here is my list:
Vacuum gauge
Set of smaller main jets (What sizes?)
Smaller size PVRs
Power valves that open later
Should I get larger air bleeds?
A set of nonstick gaskets.


Sent from my SM-T813 using Tapatalk
 

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1965 Mustang GT. 11.898 @ 113.646, all motor, three pedals
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Discussion Starter · #217 ·
Your setup looks pretty. I want to put a fuel filter in line, in case there is crud in the tank. Do you put one before or after the fuel pump?

What all should I get to tune the carb?
Here is my list:
Vacuum gauge
Set of smaller main jets (What sizes?)
Smaller size PVRs
Power valves that open later
Should I get larger air bleeds?
A set of nonstick gaskets.


Sent from my SM-T813 using Tapatalk
Primary jetting will land somewhere around 70, +/- a few sizes. If you want to block the secondary PV, add 8-10 sizes to the secondary side jetting. Nothing wrong with running a secondary PV but it depends on how hard your car accelerates. If it hooks well, you run the risk of uncovering the secondary PV and that can lean out WOT.

Main body air bleeds. If anything, it’ll probably want smaller high speed bleeds than are in it now (I think they’re .035 from the factory). The idle bleeds (assuming they’re about .070) should be about right.

It sounds like you’ve done some research 😎. Wideband O2 is a great tuning tool that I’d highly recommend.

Take lots of notes, record all changes and results. Be prepared for some frustration, it’s just part of the learning curve. But once you get it right, you won’t believe what 347 cubic inches is capable of 🤘
 

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1965 Mustang GT. 11.898 @ 113.646, all motor, three pedals
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Discussion Starter · #218 ·
About fuel filters. Some say after the pump, some say before. This will probably piss some people off… but for a street car it probably doesn’t matter much as long as you run something.
 

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If you're using a mechanical fuel pump, you'll want the fuel filter between the pump and carb because the mechanical fuel pumps push fuel better than they suck fuel. Lots of recommendations for the 65 style mechanical fuel pump as it has the canister style fuel filter on it that works a lot better than an inline filter and two less connections to worry about on the fuel line.
 
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