#461  
Old 07-15-2021, 07:19 PM
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Skip Fix Skip Fix is offline
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Here is an article I hung on to from college-found it in a box at my folks house. Modifying 4224s. Tom can give some input on his thoughts. Boy Hot Rods had freaking 205 pages back then!!
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Skip Fix
1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever!
1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand
1965 GTO 4 barrel 3 speed project
2004 GTO Pulse Red stock motor computer tune 13.43@103.4
1964 Impala SS 409/470ci 600 HP stroker project
1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs
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  #462  
Old 07-15-2021, 11:35 PM
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I HAD THE SAME MAGAZINE ON THE SHELF FOR YEARS, But,
a very good Holley Friend is putting together a Magazine "Library"
in the upper floor of his "Barn" (actually a very large storage building)
that can park 19 vehicles inside on the bottom floor and has a lot of
storage space on the upper floor where the "Library" will go.

So far I have transferred about 12,000 magazines to his library with the earliest ones
being from the 50s and the latest ones 2021. They were all of the magazine published
magazines: Hot Rod, Car Craft, Super Stock, The Pontiac magazines, the Ford magazines, all of them.

But glad he can make use of them.

The Paul Bevins article on the 660 Center Squirter Carbs is right on, except for years I replaced the rear metering plates (carbs mounted sideways) with regular jet-able
metering blocks and used the "Race Bowls" vs the "Side Hung" fuel bowls.

Thanks Skip for posting the article. You could mount your carbs in the normal North/South manner on your special cross-ram intake.

Tom V.

I still have I think 3 sets of those carbs on the shelf.

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  #463  
Old 07-18-2021, 03:10 PM
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I ran across a post from the Dominator Board I used to post on with Tuner and Markaudio from years ago.

The specific Dominator is a 3 circuit carb that was modded back to a 2 circuit carb.
Jeff (the carb guy from the Pontiac board) has done several of the 3 circuit carb to 2 circuit carb conversions. I would recommend him for the conversion as he may have some Pontiac specific mods above and beyond what I am going to post below.

Here is the information:

Hey guys,im setting up a holley 9375 dominator for a friend and doing the 2 cicuit conversion like i did on my 1095 king demon.
This is for a 496 c.i chevy bigblock with afr heads and a 248-256@.050 cam with .695 lift.

My question is this.My 1095 demon has the idle eze feature i installed for idle air.This holley does not.
Should i be drilling throttle blades for some idle air?Or should i try it without them first?

I set a set of 4150 proform blocks and carb as follows for the 2 cicuit conversion:
IAB=.070
HSAB=.026
T-JETS=.063
EMULSION HOLES 1&3=.026
EMULSION HOLES 2&4=BLOCKED
ANGLE CHANNELS=.161
KILL BLEEDS=.028
IFR'S=.036
PRIM PVCR=.089
SEC PVCR=NONE
PRIM PV=3.5
SEC PV=BLOCKED
PRIM JET=85
SEC JET=93
SQUIRTERS=42
PUMPS=50CC
CAMS=YELLOW

This is the recipe i have on my 468 pontiac that works great.Only difference is the idle air. Should i drill throttle blades on this holley since it dont have idle eze feature?

It's been my experience that holes in the plates are only needed if you can't get enough air without over exposing the T-slot.
My Dominator has .040 slot exposed with the blade shut. So, I had to get some air without exposing any more slot.

Remember this info: As related to the transfer slot, everything below the butterflies is fuel, every thing above the butterflies is an air bleed.....as you open the butterflies your adding more fuel but reducing the air...

Personally I would play with the IAB and IFR before drilling any holes in the blades...and maybe open up the TSR if you do drill holes then you may need to adjust (or remove) your "Transfer Slot Restrictor" size....

A few Dominator carbs have a bunch of slot exposed below the blade with the blade 100% closed.
You try to open the blade for curb idle air you expose more slot.
The fix is to leave the blade 95-99% closed (100% will stick) and add curb idle air either by drilling holes through the blades or on race apps by bleeding air through the air filter stud boss.

This specific Dominator needed .040 slot exposed below the blade with the blade shut. .060 holes in the blade were added with good results.

Feed-back from the guy working on the carb:
There is no t-slot exposed with blades 100% shut.
I have the butterflies adjusted to expose .020 t-slot back and front.
I put the carb on yesterday and it did need some more idle air.
I drilled .070 holes in blades and it worked perfect.
Still have only .020 t-slot showing.
The idle screws are out 1 1/4 turn and responsive.

The motor seemed to love the starting recipe i gave the carb as a 2 circuit. All I did was turn out idle screws 1/4 turn and drill blades with .070 holes.

So there you have the post and the info we provided to him.

Tom V.

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  #464  
Old 05-21-2022, 07:49 AM
GTO-relic GTO-relic is offline
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quote:
"Barry Grant started that inflated cfm number crap years ago. Well Barry is gone, Holley owns his company and his carbs, and the cow is out of the barn. "

whoever posted this, you need to do some research.

BG Demon carbs were wet flowed at 1.5" HG/20.4" water. The corresponding DRY FLOW number would actually be approx. 7.6% more than what BG rated them at, compared to a Holley, because Holley DRY FLOWS their carbs for rating. BG also gained 6% discharge coefficient for the patented scalloped air entry on the Race Demon carbs at that time, compared to a Road Demon/Street Demon with a choke horn on it. the BG owned Demon Carb. company put their test specs in writing, it's on page 44 of the Demon Carburetor manual.

so, right off the bat with an "old" vintage BG-era Demon, you can add 7.6% to their stated flow rating, and also get a 6% better discharge coefficient for then-patented scalloped entry, compared to a POS Holley w/choke that now costs $1 per cfm new. This is why used Demon carbs are flying off Ebay and Craigslist lately like hotcakes for $250-$400 each, and new Holleys are sitting with no bidders or buyers at $500-$800+. The fact that many new Holleys have Chinese, Mexican, etc. parts, and the ones still made in USA have very poor finishing QC, isn't helping matters any- Holley is now a holding company owned by people who don't even like cars, they just want ROI, and aren't even Americans, and would like all our cars crushed, and for us to go electric across the board. wake up. the NWO corporate money grabbers are in our hot rod kitchen. they now own it.

so...BG wasn't flowing carbs at 28" water, and inflating numbers. He was wet flowing at 1.5"HG/20.4"water and advertising REAL numbers. He even used fluids in the flow tests, with same specific gravity as the fuels that would be used in the car. Take any vintage Demon, multiply it's rating by 1.076 right off the bat, that's what it dry flows compared to a Holley. If it's a Race Demon, you're getting another 6% discharge coefficient for the scalloped entry, compared to anything with a choke horn still on it, even if the choke plate is removed. The scalloped entry also equalizes the front and rear barrels, as a stock Holley primaries are restricted by the clunky 1950's design choke horn.

what he DID do, was bore out the venturis of the carbs, over what Holley offered, right off the reel. BG "750" had a 1.40" venturi. Holley 750 was 1-3/8" venturis, approx. 1.375"

so...a vintage BG 750 was bored out .025" on all 4 barrels, with the standard 1-11/16" throttle plates. His "750" scalloped entry Race Demon carb, wet flowed, actually flowed around 807cfm dry flowed, that's more than a Holley 800 DP 4780, or 780 3310, which were rated by Holley using DRY FLOW.

The vintage 825 Race Demon, had 1.42" venturis, i.e. bored out another .020" over the 750 Race Demon venturi size- but it used an 850 Holley 1-3/4" throttle baseplate. Yet he only rated it at 825 cfm. Holley puts an 850 baseplate on their 750 main body, and calls it a 950. So who was inflating the numbers here ? Again, add 7.6% to the BG 825 for a dry flow number, it's actually an 888cfm carb, if compared to a Holley. Holley fudged way over that number, to 950 in their advertising, for the same baseplate/venturi combination.

BG used this approach right across the board on all their carbs. I have one of his old Holley reworks with the BG stickers on the bowls, from his pre-Demon era. All 4 barrels are bored out .025" over the stock Holley 750 size, to 1.400" - and the top is completely scalloped like a modern Holley HP. Actually Holley COPIED the BG reworked carbs to make their new HP's. Prior to that, Holley HP carbs just had the choke horn milled level with the air cleaner mounting ring. There was still a remnant of the choke horn protruding on early Holley HP carbs. BG also managed to get from 975-1025 cfm from the Holley 850 1-3/4" baseplate -- 1-9/16" venturi combination (1.562"). There was a Demon 950 with 1-3/4" throttles, 1.500" venturi, and a Demon 1050cfm carb, with 1-3/4" baseplate, and 1.59" venturi. That was a stock Holley 850 venturi opened up .030"

He did it with wider selection of venturi sizes, up/down from what Holley offered, and the superior scalloped air entry, better boosters, and higher discharge coefficient.

BG came right out and said, race motors will produce a depression of 6" water at WOT, and testing at any pressure higher than that is a moot point. Well that's only about .45" HG. However, flow testing at a higher pressure is required, to simulate all conditions the carb will see on the engine.


Last edited by GTO-relic; 05-21-2022 at 08:18 AM.
  #465  
Old 05-21-2022, 09:08 AM
GTO-relic GTO-relic is offline
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ps- BG would adjust a carb size downward in cfm, using booster changes.
the 750 Street Demon had 4 downleg boosters
the 725 Road Demon was same dimensions, with straight boosters on secondaries blocking some flow.
their 725 could be shortened to a 625cfm with annular boosters. meaning annulars could cut 100cfm

Holley did some of the same thing, but not to such a degree, on their 750/780/800 family:

750cfm 4779 Holley DP had 4 equal venturis, 1-3/8", with downleg boosters
3310-1 vac. sec. rated 780cfm had 1/16" larger secondary venturis, i.e. 1-3/8" primary, 1-7/16" secondary, with downleg boosters, so it was a slightly "SPREADBORE" design.
4780 rated 800cfm DP also had 1-3/8" & 1-7/16" venturi combination, but the secondary downleg boosters had thinner legs than the 780 vac sec, giving it 20cfm more for 800cfm total.
3310-2 onward revisions of 3310 Holley were rated 750, they had the 1-3/8" & 1-7/16" venturi combo as well, but had straight boosters on all 4 barrels that were larger, blocking some flow, losing 30cfm, so it wasn't a 780 anymore, it became a 750.
this is why the good 3310, always was, and will be, the 3310-1. it's the one with metering blocks on both ends. you can make one by putting the front blocks on both sides. but you'd still have the straight boosters on a 3310-2 and later.

Stealth Carburetors used to sell a Holley rework, it was made on any 3310 core. they would put 2 front 3310 metering blocks on it, front and back, get rid of the rear metering plate, so it was a 4 corner idler adjustable carb, and would polish out the bores approx. .020"-.025" oversize, install (4) annular boosters, drill all 4 throttle plates with idle air bypass holes, mill the choke plate off, and scallop the entry just like an old BG Holley rework. it was sold as an 800cfm vacuum secondary carb. they gained with the scallop and bigger venturis, and lost a little with the annular boosters, and ended up around 800cfm. a carb like that with annular boosters would have electrifying throttle response though.

there's a tendency to just look at the throttle plates, when judging a Holley design...take some time, measure the venturis, and look closely at the boosters.
epiphany will strike.


Last edited by GTO-relic; 05-21-2022 at 09:17 AM.
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  #466  
Old 05-21-2022, 09:41 AM
Formula jg Formula jg is offline
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X2!
I love my Mighty Demon.

  #467  
Old 05-21-2022, 10:17 AM
GTO-relic GTO-relic is offline
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BG did more with less, because he was custom tailoring carburetors for each specific engine,
whereas Holley was selling many different SIZES of carbs, in 50cfm step stairs increments, DP and vac. sec., and letting the buyer work it out, as to what one worked best on their specific application.
2 different approaches.

I called BG when he was still answering the phone, and building Holley reworks to specific applications, back in the 1990s.
He built us a Holley 850DP, for a 470 CID Pontiac, with E-heads, Victor intake, with 10:1, and a solid roller cam 242/252 Comp
this was back in the 1990's. to this day, that was the best, most responsive street carb I ever bolted onto an engine, period.
it had 4 drilled throttle plates, and the idle mixture only needed to be adjusted 1/8 turn from where he set it at. unbelievable...
He called it the "general competition" carb. Just like the later Race Demons he sold.
he was able to do this, just from the specs on the phone, for cam, CR, CID, vacuum at idle, gearing, weight, intake, headers, trans, tire size, driving style, etc.
the throttle response would rip your head off at any rpm. the owner said "this thing is scary now".
it was 4000 lb. with driver, in a 72 GTO, with 6 speed Nash, and 3.70 gears. Full stock everything. It had a stereo in it, rugs, heater, wipers, lights, and full exhaust. Like a show car. license plate, daily driven. The owner had never even street raced before, he drove it to the track, cut a 1 second (not a typo) reaction time, and it went 12.60 at 110mph granny shifting it, letting off gas completely between gears, and launched it like a school bus going up a hill from a stop.

we had tried a Holley 4781 DP first, it fouled the plugs black, stunk like gas idling, burned your eyes, had some power, but it stalled every time we hit the brakes. You could back up 20mph hit brakes, no problem, it wouldn't stall. but going forward, it would stall instantly. brand new Holley from Summit. we returned it for refund.

The BG carb, has golden brown tan plugs, in daily street driving. Perfect burn.

here's a later BG Demon to Holley comparison:

Holley 4781 DP, 1.75" throttles, 1.560" venturis- 850 cfm dry flow

Race Demon 825- 1.75" throttles, 1.420" venturis- 825 cfm wet flow.
i.e. 890 cfm dry flow.

the vintage Race Demon has 40cfm more flow, with a .140" smaller venturi
that's because of the scalloped entry, better boosters, main body, baseplate. smoother, more precise.

and it has better emulsion. 3 emulsion bleeds per barrel in the metering block, instead of only 2 like an old Holley.
the engine gets a better vaporized mixture.
and...removable/tunable air bleeds, idle feed restrictions since day 1.

BG isn't out of business because he didn't know how to build carbs, he was amongst the best at it.
He's out of business, because the company took loans against all their real estate, assets, to fund operations, like all companies do...and lost their arse during the 2008-2010 real estate/housing/banking crash. That's because a bank loan at 6%, turns out to be 200% interest over principal, with compounded interest.
He was taken out by predatory lenders and banks. Just like everyone else. Gobbled up by the comglomerates.


Last edited by GTO-relic; 05-21-2022 at 10:27 AM.
  #468  
Old 05-21-2022, 10:51 AM
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Sorry GTO-relic, Bud you know little about Holley carbs. (I worked for Holley Engineering in Warren Michigan at their Engineering Center in the 1970s.)

"whoever posted this, you need to do some research.

BG Demon carbs were wet flowed at 1.5" HG/20.4" water. The corresponding DRY FLOW number would actually be approx. 7.6% more than what BG rated them at, compared to a Holley, because Holley DRY FLOWS their carbs for rating. BG also gained 6% discharge coefficient for the patented scalloped air entry on the Race Demon carbs at that time, compared to a Road Demon/Street Demon with a choke horn on it. the BG owned Demon Carb. company put their test specs in writing, it's on page 44 of the Demon Carburetor manual.


Holley carb flowed on their Wet Stand (Same one used since WWII with Stoddard Solvent every carb designed for production). They also had wet stands at their Water
Valley Production Plant. They tested at 1.5" hg or 20.4" H2O.

Pictures of the Wet Stands are in every Mike Urich Book published.

With 29 posts total you are for sure a phony. Please remove these incorrect posts
Moderators.

Barry Grant worked as a technician for Holley carb at one time I believe at Water Valley.

So your false info is just screwing up my accurate info.

Tom V.

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  #469  
Old 05-21-2022, 03:55 PM
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Apparently the members should do their research before taking as gospel any posts
on the PY Board.

Tom V.

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  #470  
Old 05-22-2022, 07:46 AM
GTO-relic GTO-relic is offline
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you stated that Barry Grant inflated the CFM numbers. He did not. Actually Holley did, with their 950, that really flowed around 800-830.
so..why didn't that high end flow equipment you used at Holley, pick that up ?

If the Holley test equipment is so ultra-high end, how come they put .037" idle jet orifices in carburetors,
then you have to tell everyone here to change it to a .031" ?? that's 6 sizes off from the factory.

take a 400-428-455 stock Pontiac engine. bolt on a Holley 850 4781 DP carb brand new.
run it for 5 minutes. pull the plugs.
what do you see ?
black as coal tar.
how do your eyes and nose feel while the car idles in the garage ?
I've got 40 years of experience with these myself as well.
They run too rich. They always did. Let's be frank and honest about this.


Last edited by GTO-relic; 05-22-2022 at 08:07 AM.
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  #471  
Old 05-22-2022, 01:48 PM
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Quote:
Originally Posted by GTO-relic View Post
you stated that Barry Grant inflated the CFM numbers. He did not. Actually Holley did, with their 950, that really flowed around 800-830.

In my timeframe the airflow numbers were as I stated. An 850 cfm carb flowed 830 to 870 cfm at 1.5" HG or 20.4" H2O.
Since you are a young guy you do not remember the history of where Holley was forced into the CFM wars by the other carb people. I totally agree that a
750 cfm double pumper #4779 flows 750 cfm not 950 cfm like tha later advertising stated. Same deal for them #4781 850 cfm carb vsm the advertised BS that said it flowed 1000 cfm.


so..why didn't that high end flow equipment you used at Holley, pick that up ?

It did pick it up you were just not listening.


If the Holley test equipment is so ultra-high end, how come they put .037" idle jet orifices in carburetors, then you have to tell everyone here to change it to a .031" ?? that's 6 sizes off from the factory.

Never said that, that is a lie, and the 850 cfm carbs were .038" IFRs and the
750 carbs were .036" IFRs not .031.

take a 400-428-455 stock Pontiac engine. bolt on a Holley 850 4781 DP carb brand new.
run it for 5 minutes. pull the plugs.
what do you see ?
black as coal tar.
how do your eyes and nose feel while the car idles in the garage ?

First off Holley carb in the 70s when I worked there is not the same company that went bankrupts three times since I left the company. I cannot get blamed for BS that happened to carbs made today.


I've got 40 years of experience with these myself as well.
They run too rich. They always did. Let's be frank and honest about this.
In the 1970s Holley carbs were about 1.5% rich when flowed on their Stoddard Solvent/Air Flow benches. So smart guy do you know why they test with Stoddard Solvent?

40 years, good for you. Now learn to make carb statements based on a year time frame, not generic statements. 1970s carbs, 1980s carbs, really is a simple concept. Same deal with 1st Holley Carb bankruptcy, 2nd one, third one.

You are a smart guy, you just said that, post up real info based on the timeframe. Not after Holley left Warren Michigan and went south.

Tom Vaught

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  #472  
Old 05-22-2022, 02:40 PM
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After I left Holley and went to Ford Engineering, a bunch of my old Holley carb associates would invite me over for lunch and then we golfed in the Holley Golf league.

Will never forget a know-it-all young Holley Employee who was trying to make a 4 corner idle carb out of a two corner idle carb. He failed terribly. Drilled holes right thru the center section into the venturi bores above the throttle blades. So he threw the casting in the trash and took another casting off the shelf and learned from "a old timer" how to do it correctly. I heard he was later fired by Holley after he went south with the rest of the Holley "Aftermarket" Guys. The OEM PRODUCTION guys were later absorbed by Borg Warner when Holley needed money. They wound up with nice stock retirement plans from BW vs loosing their Holley jobs down south.

Marvin Benoit and Marty Brown started Quick Fuel because the people down south did not have a clue with carbs.
Chuck Gulledge started his own carb business. Steve White went to Bosch as a fuel systems engineer.

So happy for you that you like Barry Grant. Barry personally sent me my Holley TRI-POWER Pontiac Intake manifold version 3 after the first two casting needed a lot of work. The history was in the PY Forums somewhere. Barry and I never had any issues.
You seem to have an issue that I know the actual history of Holley carb.

Barry built some nice "later versions" of original Carb companies designs like the Autolite inline carb.
Too bad the set-up was only large enough for a mild SB Chevy engine.

So I will grant that you know something about the LATER history but nothing about the history before WW-II when Holley made 3000 cfm aircraft carbs that were WET-FLOWED. And all of the Engineering Carbs at Warren Michigan were also wet flowed.

Tom V.

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  #473  
Old 05-23-2022, 05:43 AM
GTO-relic GTO-relic is offline
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it's a well known fact,
the Holley 950HP, only flows around 790cfm
and the Holley 1000HP, only flows around 900cfm
for some reason Holley's awesome flow equipment,
is not capable of putting an accurate flow number on their carburetors,
It was not BG who was inflating numbers, it was Holley all along.
this is a case of blaming BG, for what Holley was actually doing themselves.
it's a blatant case of false advertising. see it below, just one case of the many threads on Holley cfm fudging.

https://www.speed-talk.com/forum/viewtopic.php?t=9463

by highhat Sun Feb 10, 2008 5:16 pm
I just called Holley this week to get flow numbers. I have a 950HP and wanted to move up to a 1000HP.
I got them to state flow numbers. They said:
950HP flows 790
1000HP flows 900/

Holley 950 carbs
Post by bigjoe1 Sun Feb 10, 2008 10:34 am
When the 950 Holley cam out. I tested one against a good known 850 I use on the dyno alot. On a 406 Chevy that was at 625 HP , the 950 LOST 23-24 HP over the 850. When I tested the carbs on my flow bench, the 850 flowed about 55 CFM MORE than the 950. The holley 950 is really a 750 main body with an 850 throttle body. Not what everybudy thinks it is.A real 850 will work well for your 434 combo.


Last edited by GTO-relic; 05-23-2022 at 05:53 AM.
  #474  
Old 05-23-2022, 06:02 AM
GTO-relic GTO-relic is offline
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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!)

  #475  
Old 05-23-2022, 06:06 AM
GTO-relic GTO-relic is offline
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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.


Last edited by GTO-relic; 05-23-2022 at 06:20 AM.
  #476  
Old 05-23-2022, 06:49 AM
GTO-relic GTO-relic is offline
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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

  #477  
Old 05-23-2022, 07:13 AM
GTO-relic GTO-relic is offline
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that's cuz BG had released stuff like this....
750 baseplate with 2 different venturi sizes,
850 baseplate with 4 different venturi sizes
850 baseplate with 2 different venturis, and annular boosters.
that's only one line, the GC RS
general competition, removable sleeve

there also was Drag Race DR, Road Race RR, Tunnel Ram TR, Oval Track OT, Blower Carb BC lines, and 4 Alky lines.
fixed venturi, or removable sleeve.
a total of 80 different RACE carburetors, using 750/850 baseplates, all custom tailored metering to specific engine combinations, based on CID, cam timing, compression.
650-1050 cfm range
Holley wasn't even on the same floor, or in the same building as BG.
in addition, there was the King Demon Dominators, and Road Demon/Street Demon carbs with traditional choke horns.
every tuning spec was published for easy reference, for every single carb.
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Last edited by GTO-relic; 05-23-2022 at 07:25 AM.
  #478  
Old 05-23-2022, 07:58 AM
GTO-relic GTO-relic is offline
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the entire Demon line was basically custom carbs,
calibrated and metered based on CID, cam specs
something Holley only did on a very limited basis.
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  #479  
Old 05-23-2022, 08:53 AM
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Cliff R Cliff R is offline
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Another entry into the market:

https://www.enginelabs.com/engine-te...it-carburetor/

Looks like they tried to correct all the issues found with Holley and the Holley clones produced over the years. Take a gander at those billet aluminum metering blocks, already tapped for quick tuning changes, even for the PV.......

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  #480  
Old 05-23-2022, 11:00 AM
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Tom Vaught Tom Vaught is offline
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I documented a NASCAR Carb for Ford Racing, back in the 2006 time frame that was similar in design.
They just wanted me to tell them what all of the circuits did. I posted about this in a Carb Thread.

"Eye Candy" for sure. Today is the day of "Write the Check" carb tuning.

I would stick with a Braswell or Bo Laws carb personally if I was told to buy a carb.
But the carb supplier will "hook" some with cash money to burn.

Tom V.

Kind of like the Trucks today with 7 computers on them.
Do a fine job, but a 64 Pontiac can still get me down the road just fine.

Tom V.

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