[Tom Vaught]

It has been a while since I posted some Holley Carb Info

Here is a Handy Holley Jet Flow Chart for Jet Calculations

Enjoy

First Column is the Jet Number
Next two columns are the Holley Jet Part Number (example 122 40)
Next column is the Holley Drilled Size (example 0.0400)
Next column is the Jet Area (example 0.001257)
Last Column is the Flow of the Jet in Cubic Centimeters per Minute (Example 117)

The List goes from a Holley #40 Jet to a Holley # 110 jet.


40 122 40 0.0400 0.001257 117
41 122 41 0.0410 0.001320 122
42 122 42 0.0420 0.001385 129
43 122 43 0.0430 0.001452 135
44 122 44 0.0440 0.001521 142
45 122 45 0.0450 0.001590 149
46 122 46 0.0465 0.001698 156
47 122 47 0.0470 0.001735 163
48 122 48 0.0480 0.001810 170
49 122 49 0.0490 0.001886 178
50 122 50 0.0500 0.001963 186
51 122 51 0.0510 0.002043 194
52 122 52 0.0520 0.002124 203
53 122 53 0.0524 0.002157 212
54 122 54 0.0530 0.002206 221
55 122 55 0.0540 0.002290 230
56 122 56 0.0550 0.002376 240
57 122 57 0.0560 0.002463 251
58 122 58 0.0570 0.002552 262
59 122 59 0.0580 0.002642 273
60 122 60 0.0590 0.002734 285
61 122 61 0.0600 0.002827 298
62 122 62 0.0610 0.002922 311
63 122 63 0.0620 0.003019 325
64 122 64 0.0640 0.003217 341
65 122 65 0.0650 0.003318 357
66 122 66 0.0660 0.003421 374
67 122 67 0.0675 0.003578 392
68 122 68 0.0695 0.003794 411
69 122 69 0.0713 0.003993 429
70 122 70 0.0735 0.004243 448
71 122 71 0.0750 0.004418 470
72 122 72 0.0755 0.004477 492
73 122 73 0.0790 0.004902 517
74 122 74 0.0800 0.005027 542
75 122 75 0.0820 0.005281 566
76 122 76 0.0840 0.005542 587
77 122 77 0.0855 0.005741 615
78 122 78 0.0870 0.005945 645
79 122 79 0.0890 0.006221 677
80 122 80 0.0890 0.006221 703
81 122 81 0.0920 0.006648 731
82 122 82 0.0940 0.006940 765
83 122 83 0.0975 0.007466 795
84 122 84 0.0983 0.007589 824
85 122 85 0.0985 0.007620 858
86 122 86 0.1000 0.007854 890
87 122 87 0.1015 0.008091 923
88 122 88 0.1025 0.008252 952
89 122 89 0.1045 0.008577 987
90 122 90 0.1055 0.008742 1014
91 122 91 0.1085 0.009246 1080
92 122 92 0.1100 0.009503 1150
93 122 93 0.1125 0.009940 1205
94 122 94 0.1155 0.010477 1260
95 122 95 0.1165 0.010660 1320
96 122 96 0.1195 0.011216 1375
97 122 97 0.1210 0.011499 1440
98 122 98 0.1240 0.012076 1500
99 122 99 0.1260 0.012469 1570
100 122 100 0.1280 0.012868 1640
101 122 101 0.1282 0.012908 1713
102 122 102 0.1285 0.012969 1780
103 122 103 0.1300 0.013273 1850
104 122 104 0.1340 0.014103 1950
105 122 105 0.1370 0.014741 2063
106 122 106 0.1410 0.015615 2139
107 122 107 0.1450 0.016513 2240
108 122 108 0.1470 0.016972 2300
109 122 109 0.1500 0.017671 2420
110 122 110 0.1560 0.019113 2520

Tom Vaught

[Tom Vaught]

Been awhile since I posted here but wanted to pass on this Fuel Bowl Tip.

HOLLEY BOWL SWAP, FRONT TO REAR & REAR TO FRONT

I've used them swapped over like that for years on an 800 and 850 double pumper.

Primary bowl on Secondary side: Set fuel level to bottom of threads and then lower the level by 4 flats on the Needle and Seat Adjuster Nut.

Secondary bowl on Primary side: Set fuel level to bottom of threads and then raise the level by 4 flats on the Needle and Seat Adjuster Nut.

Tom V.

[amcmike]

Originally Posted by Tom Vaught

Been awhile since I posted here but wanted to pass on this Fuel Bowl Tip.

HOLLEY BOWL SWAP, FRONT TO REAR & REAR TO FRONT

What the idea behind swapping them?

[ta man]

I've used the the rear for setting idle for a few years. I still get the odd funny look from guys when I'm changing my idle at the track using the rear. Both my carbs are set up with a nice knurled screw that I can easily reach and adjust.
Thanks for all the tips over the years.

[Tom Vaught]

A post from the Chevrolet Board answers that question.

"Anyone have any experience with some Frankenstein creation like this?

My friend just bought some parts, one of them being a 4779 Holley (700 DP, don't know the -number), 4150, dual metering blocks Prim #11173 and Secondary #11166...

But the bowls have been changed from the center-hung floats to the single feed, banjo bolt fitting, adjustible float bowls. It has two primary bowls, because its still has the "secondary" accelerator pump. Looks like the fuel transfer tube holes have been plugged (another sign that it is using a primary bowl on the secondary side), and it has a "T" in the fuel line, so both bowls use their own hose/banjo fitting for the fuel line.

Not sure exactly why it was done, but I suspect it was to gain clearance in the carb enclosure, although I have seen regular Dual Feed DPs fit...

The carb fits inside a enclosure for a '66 Shelby Mustang Paxton supercharger setup setup...

I can see the DP linkage, the base plate has the second pivot stud and lever, the main body has the secondary squirter..."

More Clearance for some Bonnets or enclosures like the Vortech or Paxton Carb Box,
but most likely for the earlier Shelby/Paxton Box.

Tom V.

[Tom Vaught]

Here is a link to carb numbers I provided to a member in the street section.


His carb was R80777 4150 carb 650 cfm

The info on Holley carbs can be found here:

https://documents.holley.com/techlib...al_listing.pdf

About 12 pages down the document.

Tom V.

Now everyone will know where to look.

[Tom Vaught]

Today I will post a bit about Center Squirter Holley Carbs.
Many people are aware of the 660 cfm #4224 Holley carbs with the center squirter
design and the 1-3/8" Venturis and 1-11/16" throttle blades.
These carbs were used on hundreds of Chevrolet SB Chevy Drag Race engines.
AND a few Pontiac Engines like Richard Burnhart's GTO.

The 850 CFM #4223 center squirter carbs had exactly the same design but had the normal 850 cfm carb venturis and the slightly larger 1-3/4" throttle blades.

These were the LARGEST MECHANICAL SECONDARY (NON DOMINATOR) RACE CARBS OFFERED IN THE EARLY DAYS. i have provided some pictures below showing the features of the carb.

Tom Vaught

ps my computer had a computer glitch and would not allow me to post pics or excel file info for a few days so the Tri-Power info for 1965 and 1964 has been on hold.

[Tom Vaught]

He really did not do much to the carbs as STOCK, (per the Holley Specification Manual)
1-1/4" Primary Venturis, and 1-5/16" Secondary Venturis, and the Normal 1-11/16"
Throttle Plates in all 4 spots.

He might have pointed out the "750 base plates" but those base plates were all all 650 to 800 cfm Double Pumper Carbs and and also just about every 750/780 cfm Holley carb. A couple of oddball Ford Carbs used a different baseplate and different sized throttle plates.

So a lot of smoke and mirrors but not much different from a stock 660 carb (if at all different). The mechanical opening linkage and the center squirter 4 tip nozzle is the main difference along with the 50cc (5cc per stroke) accelerator pump.

Tom V

[theamcguy]

I had forgotten about this thread until Tom started posting in it again. Lots of great information here, Thank you very much Tom for posting all of it. After going through all 444 posts and pulling out all of Toms' info; I now have a 230 pg word document. Tom you did a lot of typing for sure, Thank you so much for your efforts.

[Tom Vaught]

Thanks Very Much. Glad to pass on the info.
Several people have told me I should write a book.
One reason why I started this thread was to pass on Holley Info
so people did NOT HAVE TO BUY A BOOK, LOL!
No need for that deal as Mike Urich (my old boss) already wrote those books years ago.
Mike Urich was Manager, Holley Aftermarket Engineering when I knew him.
Chuck Gulledge was one of his best Holley Engineers, very sharp. Later a top Pro Stock
carb builder after he left Holley.

Mike Urich was later a Vice President of Engineering at Holley Carburetors.

Read his stuff first and then later blend in some of my posts with that info.

Tom Vaught

[Tom Vaught]

WOW, Last post on Holley Carb information was by me was July 06, 2020.

Time to add a few pieces of information/history. Specifically on a very special Holley Carb designed by Holley Engineering for the 1966 Le Mans 427 single 4 BBL GT-40 Engine. This carb was the very first Center Squirter
Carb and the first carb with the unique "Nose Fuel Bowls" and with full mechanical secondary activation vs Vacuum secondary activation. Other carbs might have one or more of the above but not all of them.

I will also post some pictures of the unique parts of the carburetor.

So Picture #1 is a throttle linkage side of the carb with the "Nose" Bowls.

Picture #2 is another carb/ engine picture showing the right side of the engine and the special headers for the engine.

Picture #3 is the top view of the carb in the Ram Air Enclosure. You can see it is a Center Squirter Carb and has almost immediate secondary opening on the 780 cfm carb. A very Rare Carb used by Ken Miles who wanted full mechanical control of the throttle operation. Holley later updated the carb to a 850 cfm center squirter model.

Picture #4 is a close up view of the carb. These carbs were later used as Tunnel Ram carbs.

Last picture for today, here you can see the Holley "center squirter" carb on the 427 engine in Ken Miles Ford GT-40
race car. (car #1)

Tom V.

[4zpeed]

Originally Posted by Tom Vaught

WOW, Last post on Holley Carb information by me was July 06, 2020.
Last picture for today, here you can see the Holley "center squirter" carb on the 427 engine in Ken Miles Ford GT-40
race car. (car #1)



Tom V.

In a bit of respect and history, what a shame about Ken Miles in the 1966 24 Hours of Le Mans, all because someone wants some publicity, very unfortunate.
Then to loose his life and never get another shot. Sometimes you get the short end of the stick, sometimes you don't even get a stick.


On a better note, glad your back from vacation Tom, been missing school and could always use some education. Love the 780's but never seen one of those.

I always thought 780's were awesome carbs right out of the box, and my go to carb for Pontiac and Olds 400's, always worked very well for me.

Question is, how many revisions or versions of the 780 has there been, not including factory equipment units, just over the counter type?

Please try to be explicit as to what point it was they turned to chit, i.e. the higher IFR location and move from Zinc metering blocks to the Aluminum stuff.

I imagine this info could be useful to myself and others as it most likely pertains to most historical era Holley's as apposed to the newer type units.

Pic of metering block showing improper higher IFR location, from the 12-26-2017, 09:10 AM post in this thread.

Zinc to Aluminum material info from this thread https://forums.maxperformanceinc.com...d.php?t=849490.





As Always, Much Thanks!

Frank

[4zpeed]

An effort to consolidate and means to navigate, this bit of info is pulled from the 05-18-2019, 10:05 AM post of this thread and pertains to the best location for the IFR.

Originally Posted by Tom Vaught

The best location for the IFR (Idle Feed Restriction) was identified in carburetors and the results reported in NACA REPORT #49 (Part II on page 607) See link below.

http://naca.central.cranfield.ac.uk/...-report-49.pdf

In the conclusions part of the document, conclusion #4 clearly states that:

"Submerged Fuel Metering Passages (IFRs) are free from Instability and Irregularity of discharge when the head is very small."

You can not have a submerged Fuel Metering Passage when the IFR is in the "HIGH" Position, (only the "LOW Position").

There are 10 other conclusions and all of them are correct.

Many Carb Tuners have converted back to the Low Position IFRs even though the Holley Carb came stock with the High Position IFRs.

Hope this helps.


Tom V.

Again, Much Thanks Tom,

Frank

[Tom Vaught]

I believe that link no linger works but here is a attempt to post the info in a screen shot, (looks like it worked).

Look at point #4

Tom V.

[4zpeed]

Originally Posted by Tom Vaught

I believe that link no linger works but here is a attempt to post the info in a screen shot, (looks like it worked).

Look at point #4



Tom V.

Appreciate that, it's been broke, didn't know if it was me, at times I have issues loading pages.

Sometimes I wonder if there's a conscious effort to subvert info in a attempt to prosper from it.

One of the very reasons I'm grateful for all the info provided freely by everyone on the forum.



Thanks'

Frank

[GTO-relic]

in their haste to get 950-1000 cfm versions of their own 850 design to market,
Holley was just labeling their carbs with cfm numbers, to match Demons actual latest offerings,
the difference being, BG carbs really DID flow those numbers.
Holley carbs on the other hand, did not.
we all knew this was happening.
here's another example:

https://www.speed-talk.com/forum/viewtopic.php?t=13627

750HP main body and 850 base plate....
Post by ROG30Y » Wed Nov 26, 2008 3:28 pm
cant remember if ive asked this before.
is there enough material in the 750hp main body to port it to a 850 base plate?
Top

Eric68
Post by Eric68 » Wed Nov 26, 2008 4:52 pm
I believe they will bolt together and you will have a 950 (flows roughly 830 cfm)
E85 racer and E85 carb builder
www.horsepowerinnovations.com


ric3529
Post by ric3529 » Wed Nov 26, 2008 5:48 pm
this may seem like a dumb question , but why would adding a 850 base plate to a 750 main body, give you a 950 ??( that flows 830 cfm) if the missmatched parts flow 830 what will a 950 flow (if there the same ) im not asking this as a smart a%^ just dont understand ?? thanks Ric

by MadBill » Wed Nov 26, 2008 5:52 pm
950 is just a number; it only looks like a CFM rating. (Thanks a heap, Holley!)

[Tom Vaught]

Been a while since I posted on the Holley Carb Sticky.

I was looking at some Hot Rod Magazines I plan to donate to a retired Holley Guy I worked with back in the 1970s. He is putting together a "Library" of information that was printed in all of the old paper magazines, like Car Craft, Popular Hot-Rodding, Hot Rod, etc. I have donated to him about 6 thousand magazines so far. Still have a lot to deliver to him at a later time.

So I ran across a Hot Rod Magazine dated Hot Rod 2013 JULY and I will talk about an article called "The Holley 6 Pack Carbs, on Jim Mooneyhan's '70 Dodge Coronet, 440 are messed up. We are going to fix them.

So without typing the entire article, I will post the Issues that Mr Mooneyhan has with his 6-Pack set-up:

1) The car (engine) idles too fast.
2) The Throttle Response is bad.
3) There is a lean surge at 55 mph.
4) The engine seems rich at idle.
5) Turning the Idle Mixture Screws or Idle Speed (Throttle Blade) Screw has no effect.

Info: The End Carbs are original 440 6 Pack carbs. The Center Carb, He said, was correct for a 440 Six Pack set-up with auto trans. This info is from Marlin Davis, a Hot Rod writer. So they took the car to "Joe's Garage", a shop in California apparently.

It was delivered on a trailer to the shop and when attempting to get it off the trailer it had a 4000-5000 rpm "idle".

Initial Diagnosis showed the following issues, as received:

a) A bent "Divorced Choke" linkage. Choke was not completely allowing Curb Idle speeds.

b) Center Carb had a "Blown Power Valve" Normally this would not be an issue at idle but at 4000 - 5000 engine rpm would be adding fuel to the engine increasing the speed.

c) Center Carbs intake manifold gasket was damaged (leaking), allowing increased idle air into the intake.

d) Center Carb had 90 main jets on the center carb (normally used on only the rear of 4 BBL carbs unless you are racing a Dominator Carb). 6 Pack rear carbs use Metering Plates vs Metering Blocks.

e) A 50cc Accelerator Pump was installed on the Center Carb. In some cases on 850 cfm #4781 carbs for racing this mod works with the large cfm primary barrels. NOT on a small center carb on a 6 Pack set-up (which was later identified as a 340 6 Pack carb, not a 440 center 6 Pack carb).

f) "An Idle Air Bleed on a "end carb" was blocked".
Just for information for the guy who was given the info about the carbs, THE INNER AIR BLEEDS ARE THE HIGH SPEED AIR BLEEDS. THE IDLE AIR BLEEDS ARE THE ONES CLOSEST TO THE OUTSIDE OF THE AIR HORN RING. The blocked air bleed was a high speed air bleed.

g) The End Carbs had "sticky" throttle blades. Not opening and closing smoothly most likely caused by the other issues and a lack of maint by the owner.

h) Two bad plug wires and fouled spark plugs.

i) Idle vacuum at best was 5" of idle vacuum but the engine was pumped and found to be solid internally.

Fixes: Basically fixed all of the issues mentioned above, converted the Holley center carb to a 440 center carb calibration. Not sure what the Holley people told them to do vs just replacing the carb with a proper 1970 Holley 440 center carb which Summit/Holley was selling at the time. I would have put the right center carb on the vehicle immediately. Today 2021 that may not be as easy to do, back then they were available.

(I fixed a Ford Guys Holley Tri-Power Set-up one time (for free) after the guy had a shop Powder Coat the carbs vs (have them dipped properly) and "unplugged" most of the air bleeds in those carbs, along with putting the right calibration in the carbs.)

SO THE POINT OF THIS IS, TAKE YOUR HOLLEY CARBS TO A SHOP THAT ACTUALLY KNOWS HOW TO WORK ON THEM PROPERLY. Especially if they are rare set-ups.

Tom V.

[GTO-relic]

now...what good is that cutting edge Holley flow testing equipment, if the number the carb flows, is not put on the carb itself after flowing it ?
it's a fact, NO ONE even HAD a 28" flow bench in the entire Big Three, carb makers, or anyone else...until Smokey Yunick built one sometime in the late 1950's-early 1960's. they were all out to lunch technically. an old timer WWII bomber pilot had to build one, with no formal college education. He quit school to support his family on a farm as a kid.
no college education.

what's that say about the auto industry, and aftermarket parts mfrs. ?

BG Demon caught Holley with their pants down,
and Holley was scrambling madly doing damage control...
Holley's arse was in the wind with overly-rich metered carbs, for 40 years.
they were an easy target for BG to beat, and improve on.
BG understood a Holley design, better than Holley did.
because he realized it's foibles, and weak points, and he figured out how to fix, and redesign them better.
that's why Holley quickly bought Demon, when the latter went bankrupt.
Holley was scared to death that Demon could put THEM out of business.
Holley had been making substandard, poorly metered carbs for decades.
they were a wide-open only carb from day one.
the Qjet guys all know this. Qjets are to Holley, what Demon was to Holley.
Qjets and Demons, are better carbs than Holleys.
Holley being a globalist conglomerate now, doesn't want competition.
Competition to them, is a sin.

[64gp4spd]

Tom, Great Thread I have a question regarding idle mixture screw adjustment.
I have a Holley HP950 Street carb on a Torker 2 intake, with 1 inch spacer
Engine is 463, Kauffman Heads, 11:1 compression. around 12-13 inches of
vacuum at idle. It seems to run and idle really well, but
I am not getting much adjustment out of the 4 corner
idle mixture screws.
I noticed through the sight glass that the fuel levels
front and back were high so I lowered the float levels to where the fuel level
in the center of the sight glass. I did see in this post that the throttle blades
may need to be readjusted. Can you tell me what the process is to re-adjust
the blades?

Thanks, Rich

[GTO-relic]

Holley came out with the HP series,
to copy the BG patented scalloped entry,
billet pieces, etc.
BG's offerings were obviously so superior,
Holley had to upgrade their entire line.
they didn't have custom venturi sizes like BG,
they simply bolted an 850 baseplate, onto a 750 main body,
and called it a 950. Holley basically admitted, it was marketing hype,
by stating their 850 made more HP at WOT applications.
they also copied the BG sight windows in the fuel bowls.

https://www.motortrend.com/how-to/mo...true-hardcore/

Background

Holley introduced HP carburetors back in 2004, with new features such as removable air bleeds and a contoured main body. Those features were a significant improvement over the previuos style 4150 carburetors that existed, but over the years racers have asked for even more features. While the HP carbs do have some adjustment capability, the idle circuit and the power valve circuit are still controlled with pressed-in jets. With the advent of low cost, wide-band meters, the demand for fully adjustable metering has greatly increased. For that reason, Holley recently introduced a complete redesign of their classic 4150 series carburetors. These new carburetors, known as the aluminum Ultra HP series, are so loaded with new features that they make the previous 4150 models obsolete--not really, but you know what we mean. In the interest of keeping our readers in the know, we put one of the new Ultra HP carburetors under our microscope, and then bolted it on the dyno. Living up to the buzz, this new carburetor performed perfectly.

A True 950

There has been some confusion over the last several years about the 950HP carburetor that Holley sells. Many people assumed that since Holley calls it a 950HP, that it actually flows 950 cfm. More experienced people knew from looking at the specifications, that the 950HP used a 1.38-inch diameter venturi which is the same size venturi as the one used in the 750-cfm carburetors. As a point of reference, 850-cfm carburetors use a 1.56- inch venturi, and 650-cfm carburetors use a venturi with a diameter of 1.25 inches.

While I'm sure that the marketing guys at Holley had a good reason for introducing the 950HP and 1000HP carbs with those names, it did cause a certain amount of confusion in the marketplace. It's still common to hear someone mention that they are going to pull off their 850 carb and "step up to a 950." The ironic thing is that in many cases, the 950HP actually works better than the 850. Not because it is bigger, but because it's smaller. The smaller venturi size provides increased air velocity and a better booster signal for improved part-throttle performance. While the smaller 950HP works well on the street, for all out racing the 1.375-inch venturi size can limit the power output.
The large sight windows are visible on the sides of the bowls. Also notice