[GTO-relic]

has anyone tried the new Edelbrock 4150 VRS Holley-style carbs on a Pontiac yet?

https://www.edelbrock.com/vrs-4150-carburetors

[MatthewKlein]

I've seen a few videos about them and a tour of the factory production area. Looks like a nice piece.

What confuses me is the decision to copy that style carburetor. They must be banking on holley transitioning away from carburetors.

Personally I would like to see an updated version of the quadrajet/thermoquad.

[steve25]

One great thing about those is the external idle air adjustment.

The original Carter AFB carbs from the early 60s had them and I can’t believe it’s taken these many decades for such a feature to come around again!

[Kenth]

Looks like they added two more places for the fuel to leak from.

[Formulajones]

One thing I've noticed from the photos and videos I've seen on them is they are using their own style of bowl gaskets,.....of course. So if ya need one of those while in the road good luck finding them, better carry spares. I wouldn't be shocked if the meter block gasket is it's own as well.

Seems every time these new renditions of a carb comes out there is something about them unique that wont interchange with the carb they copy. That's why I avoid them. I can still stop at any auto store and grab gaskets, needle seats, and power valves when I'm in a pinch for a good old fashion Holley carb.

[GTO-relic]

dry flow is what exaggerates cfm numbers on a carburetor.
but even if someone did flow the VRS 850,
at 1.5" HG/20.4" H2O standard,
it's going to flow a lot less than a Holley 850.
Holley got all that BG plant/equipment flow gear,
from the BG Demon bankrupcy buyout,
back around 2010-2012.

[GTO-relic]

the smoke and mirrors cfm game was exposed decades ago.
this has all been documented, hashed out 20-25 years ago.
the buying public is smarter now, which is why that Edelbrock VRS will flop.
no one on this site has even replied that they bought one yet,
what's that say ?
here's why:

[GTO-relic]

the VRS is 1/2" taller and that's a problem with some cars especially Firebirds, that are already close to hood from factory.
I can barely fit an 800 Holley vac sec carb on my '70 GTO under the stock hood with a Victor intake and and air cleaner,
that's with the choke air horn already cut off and sculpted inlet all done by a custom carb shop.
had to cut the carb stud down, and also grind ears off the carb wing nut. I mean it barely fits with a standard open element air cleaner.
but I can sweep a screwdriver or clothes hanger under the hood with it shut and carb/air cleaner in place.
no way this carb would fit under a stock Pontiac A, F, G body hood with a Victor intake.
maybe if the vent tubes were cut off.
I'd assume the same problem with high riser intakes on a Camaro, Chevelle, 442, GS, Monte Carlo, Mustang, etc.

[GTO-relic]

If Edelbrock makes a "950" carb,
which they said is in the works,
that will be in the ballpark for a big block 455-500 engine.
because then it will finally have a throat size,
similar to compete with the old Holley 850 style BP family of carbs,
everyone has been running for 55+ years.
If they abandon the annular boosters,
and make some downleg booster carbs, with larger venturi.
then they have something, to build on in the future.
we can't even get the emulsion/air bleeds from them,
for the carb. what good is it then ?
and we have to rely on Holley jets, power valves for the VRS as well.
it seems like a half hearted market test by Edelbrock on the surface.

[GTO-relic]

Originally Posted by steve25

One great thing about those is the external idle air adjustment.

The original Carter AFB carbs from the early 60s had them and I can’t believe it’s taken these many decades for such a feature to come around again!

that feature has been around a while. Qjets had it on the lid up front in the 1970's but not a high degree of adjustability. the original BG Demon carbs had it in the air filter stud boss, you could remove the threaded stud, and use a long screwdriver and adjust it. what happened historically was this: BG Demon brand upgraded the Holley in 1990's, Holley had to spend some money to compete and introduce the HP line. then Holley sued BG in court. eventually BG went bankrupt, and Holley was right there like a vulture buying all the existing factory machinery, carbs/parts, and buildings. Holley then continued to make the Demon carbs, first finishing up what was in house in process, then changing them for the worse and cheapening them- until they were no better than a standard Holley or in some cases worse. But along the way they got all the Demon improvements. Now Edelbrock took all those Demon traits and put them in the VRS. Threaded emulsions jets, idle jets, top idle air bleeds, sight glass bowls, idle bypass adjustment, billet metering blocks, 4150/Dominator interchangeable baseplates, interchangeable boosters, etc. were all features invented by BARRY GRANT on their top line RACE carbs. these companies steal shamelessly and stomp on the ingenuity of the little guys, then take their inventions and call it their own, and re-release it. they're banking on a couple decades no one being around that remembers. Holley immediately announced all the BG features as shamelessly their new own inventions when they bought out BG, now Edelbrock is doing the same thing. reason being today's Holley, Edelbrock are not the same companies of old. They are opportunistic and owned by holding companies, faceless investors nobody ever gets to actually see.

[GTO-relic]

ok...using that high end, big dollar flow equipment,
we know these sizes venturis, butterflies wet flow these numbers,
and this was WITH a fully sculpted top inlet, no choke horn.
the Race Demon patented sculpted inlet, everyone now copies, uses,
look at the difference in flow drop, when annular boosters are used,
no other changes- the flow drops 100-200cfm for same butterfly/throat size
ALL the Edelbrock VRS carbs have annular boosters, and smaller throats.
look at the flow charts from 25 years ago:

[GTO-relic]

looks like the sizing is way off
Summit Racing actual buyer's review


· 10 months ago
Excellent But Smaller Than Advertised

Excellent Carb But it's in no way the same size 750 cfm rating as a Holley or Proform 750.
It responds to every adjustment.
Slowed 2 tenths and 2 mph.
Other than the cfm description it runs great probably best for street.
Posting side by side photo

[GTO-relic]

btw, BG never made a 750 Race Demon with a normal 1.375" throat.
they were all hopped up to 1.4", 1.42"
he did that for a reason. they were somewhat flow limited.
he had been porting/polishing the 4779 since 1980's,
and sculpting the inlet.
when time came to make one from scratch,
he opened up the throats a bit, right in the casting from the get go.

[PAUL K]

Originally Posted by GTO-relic

btw, BG never made a 750 Race Demon with a normal 1.375" throat.
they were all hopped up to 1.4", 1.42"
he did that for a reason. they were somewhat flow limited.
he had been porting/polishing the 4779 since 1980's,
and sculpting the inlet.
when time came to make one from scratch,
he opened up the throats a bit, right in the casting from the get go.

You're original post said BG never offered a 1.4 venturi 750 with annular boosters.... That is misinformation, they did.

One can't debate or learn from a person that changes mis-facts as he goes along.

Let's changed the subject and you can fill us in on your 1,000 horsepower 4X head project.... How is that progressing?

[GTO-relic]

actual JEG'S buyer review 750cfm VRS
he gave it a 1 star out of 5
returned it.


★★★★★
1 out of 5 stars.
· a year ago
Nicely executed, no support, possibly design flaw.

This is a very nice looking carb, fully adjustable, except for maybe some engine sizes (spec). Also, Edelbrock has zero support, I called them 3 times in 2-weeks and received no call back. I ran this carb on a fresh Ford FE big-block (445ci), moderate build - Edelbrock Performer RPM intake, Edelbrock 60065 heads, and Comp Cams Hyd Roller (230/236@.050, .530 lift), pulling 12in vacuum at 800rpm (4-speed car). I'm familiar with how 4150's are tuned, including air jets, emulsion jets, etc. I could not get this carb to run at cruise above 11.5AFR, I was targeting 13.0AFR cruise (1800-2700rpm). With this engine spec I don't see that it's possible, so maybe this carb would work with a built small block, but a big block with high initial booster pulse I don't see it working, even with all the adjustments that are possible. I was told it's because the Throttle Bore (1.68") and small Venturi (1.25)" size causes too strong a pulse on a bigger motor with lots of vacuum, I don't know how true that is, but it makes sense, so be careful. Again, with zero support from Edelbrock, it's a hard sell. I tried approximately 25 different combinations with the emulsion jet stacks, air jets, and of coarse - main jets. Returning carb. 2-weeks of tuning time - lost.

[GTO-relic]

now, are we supposed to believe, a 1.39" throat, with annular boosters, without a sculpted inlet, can flow 850 cfm ?
they obviously don't because everyone is already complaining, losing 2 tenths, 2 mph, losing 150HP on the dyno, still down 16HP after tuning, going rich at 4000rpm even with the power valve hole plugged, and returning the carbs.
they can visually SEE the venturi is a lot smaller, then have trouble tuning it.
they don't even need a flow bench. their cars are slowing down, and the dyno numbers are falling drastically.

[GTO-relic]

tech thread:

EDELBROCK VRS-4150 carbs, anyone using?
Hello all, I am a noob compared to you guys but I I have this carb on my '78 Bronco and its pretty dang awesome! All my friends said I was dumb to get a racing carb for my old rusty ford but they haven't ridden in it so whatevs...
I need help from you guys please tuning the secondaries a bit and have some specific questions about air bleeds relating to RPM (high speed/intermediate/low speed) etc..
Here is a photo that describes the metering block better.
Problem When I go WOT it starts at ~15 AFR and climbs down to the 12s and then 11s if you hold it to the floor. Also at high speed cruising it seems to still go rich into the 11s withough the power valve in use. This leads me to believe that the intermediate or high speed emulsion jets need to be downed a bit, or possibly a bigger air bleed on the top side of the carb for int#1.
My truck is limited to 4200RPM currently so I don't even know if I'm getting into use of the High Speed Bleeds(the green ones in my pic below)
More details below the pics...Thx in advance. I posted here because its the forum that has the latest results for this carb (seems the most current old school type forum interested in this carb).
Forum won't let me post pics due to being a new user. I will post pics later. I also have videos posted on Rumble under "Ricky Ace Wrenches"

"Buck the Truck" - Mall Crawler / MobileMudRainbowFactory for now.
'78 Ford Bronco
351M - 4 spd manual
Fenderwell header and Thrush cherry poppers
MSD 6AL limited at 4200
manual fuel pump
Edelbrock Dual plane intake
Idles around 900rpm warm @ 185
AFR/tach/vac gauge in cab (for tuning)

[GTO-relic]

youtube dyno shootout VRS vs Pro Comp
out of box the VRS only made 400HP
after tuning VRS was still down 11HP compared to their old Pro Comp 780

https://www.youtube.com/watch?v=Jb09TdY1GKo

description under video on youtube, 408" SBM Mopar

861 views Dec 30, 2023
This is the Dyno Run with of the 408 in the last video. Has the Speed Master CNC assembled heads. They were checked over and were good. We tried the usual 780 Pro Systems carb and an Edelbrock VRS-4150 750 carb. Out of the box the Edelbrock made 400 hp. After tuning it, we still only could get 516 hp. The old Pro System carb made 527 hp and more torque.

[GTO-relic]

a picture is emerging....if you get a VRS, get the 850.
or...supposedly there's a VRS 950 in the works, get that instead
the 650, 750 are for stock motors with stock int/ex manifolds, stock mild cams
the VRS is no where even near a real race carb.
not even in the same building or on the same floor...

[GTO-relic]

one of these with 1.75" throttles (Holley 850 size), and 1.42" throats, downleg boosters, sculpted inlet, flows 825 cfm.

put annular boosters on it, they're bigger, block airflow. it would probably flow 725 cfm, or less.
that's what the VRS has, on even smaller 1.39" throats.
the inlet on the VRS is not sculpted. 850 cfm from a VRS 850 is an advertising gimmick.

in reality, the 825 isn't even big enough, for a 450-500" engine- it can use a 975cfm carb no problem.

http://52.55.101.62/archives/2001/09/project460/