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Holley 830 cfm w/annular boosters

12K views 62 replies 20 participants last post by  427L88 
#1 ·
Folks, methinks the scuttlebutt on these is to steer clear, due to the annular boosters going lean at rpm. New engine wont be the same RPM monster the 427 was, wondering if this setup is acceptible to 6000 rpm. 467 c.i.
 
#3 ·
Gene,I have a 825 Mighty Demon with annular boosters that's been on my big block 468 and now 513 for quite a few years.
I have never encountered any lean conditions.
It flat out works awesome !!!
Guy
 
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#17 ·
Ran that same carb on the 454.070 with Dart Rec Port heads. Was very responsive. I may be off base but I question if you need to run an annular carb as fat as a downleg due to the better atomization of the fuel. Archived somewhere on this site should be post from chassis dyno session. Baselined with the BG 825 annular, swapped on Vince's dialed in Prosystem 950HP, then back to the annular rejetted. Ultimately, the BG 825 produced higher torque, not by much though. On the street the annular felt like fuel injected car though with the throttle response. At the track, seemed every carb from a Holley 750HP street to the BG 825 annular to a 4781 hit the same mph within maybe .5 mph, which we always felt was within margin of error for temp/humidity, track conditions, etc.
 
#4 ·
Annular boosters themselves don’t cause a high RPM lean condition. I shift at 8000-8200 RPM with annular boosters and plan to shift at 9000 RPM on my next iteration of overgrown SBC (1000+ HP target goal)

If that were the case annular boosters wouldn’t be used in 4500 dominator series carbs.

It may be that the stock 830 calibration needs a HSAB change.
 
#5 ·
I think like Jason said, the early 4150 carburetors with annular boosters sometimes encountered those types of problems and they couldn’t be tuned out due to the non adjustable nature of them. Later on as air bleed changes and mods became standard they started to gain a following. I was one back almost 15 years ago that had a demon carb that would not come off the transbrake clean and had issues on the dyno. 2 old downleg 850 carbs ran cleaner than the demon did with annulars. It wound up being sent back to Barry grant to be converted to downleg.
 
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#6 ·
Here is the problem with the line of A/D booster carbs from Holley, the boosters are junk and that's not from me that is what BLP told me. They said the problem is the hole pattern in the booster is pretty poor on them, BLP has new Booster inserts that are really easy to install and fixes the lean problems. Always wondered why they sold a 12 hole booster and Holley uses 6. Both of my Holley A/D carbs were lean on the dyno no matter where we jetted them but the same type carb with a down leg booster was spot on. The 1000hp was at 14.3 to one even with a ton of jet, even changing bleeds make it fatter at the top end and really pig rich at the bottom. I have 2 Demon's with A/D boosters went up 4 jet sizes and were dead on at 12.8 to 1
 
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#8 ·
Dont fret novadude, a Qjet will be used for most "OTR" duty, but the Holley ought make more power for ET. I have an old 850DP that's fresh and ready to go, even thought about pulling the boosters in it and putting aftermarket in, if only to modernize the old beast. Or pick up an annual carb direct from Holley refurb'd. Looking to really bolster the throttle response, so it feels like a blower car. :)

68 Chevelle, I suspect this is the issue that the engine builder saw on the dyno and doesnt prefer them for that reason.


Curious to see how much the Qjet loses over the Holley on this engine. Hope to find out on Tuesday when Mark runs the dyno test! All I know is that the heads are flowing really, really well at mid lift, so it should put down the power. How much the Qjet loses will be the question.

And yes, it will look "similar" to a 325hp 396. I cant use that stupid restrictive air cleaner however. Therefore I'll dress it down as a 350hp/396 w/ painted intake ( being that its a modern GMPP).
 
#10 ·
Yes, and no issues at all when it was run prior to the tripower install over 10 years ago. Just looking to optimize everything is all. I may even stake new aftermarket boosters in for next year in lieu of buying refurb from Holley, so wanted to hear others experiences of A/D vs downleg.
 
#13 ·
Gene, a little off topic, but which one of Marks engines did you decide on? Looking back in past posts, can't find that info. What's the specs?
 
#14 ·
Darren, a 467 with full head work and a hyd roller. GMPP dual flange mani so I can pop a Qjet on there for long road trips, as the old 850DP is a ravenous pig. I had ^almost^ thought of staking new boosters in when I went thru the carb recently ,as so many carb gurus preach on A/D boosters, but let it alone, as it ran fine before.
 
#16 ·
Darren, a 467 with full head work and a hyd roller.
Which cam were you planning to use? I thought I saw somewhere you were going with the Isky H-roller 228/238.
 
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#19 ·
I told that to the guy that dynoed my 421. I gained about 20hp with his dyno carb.
I was kinda disappointed.
 
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#18 ·
Not likely Bob, but I have asked Mark Jones if he could A/B test a Qjet and his 1050 Holley mule during the dyno session. He suspects it will be down a bit and I have no reason to doubt him; I'd like to see how much is all.

Joe, its the throttle response of the A/D I was seeking, to really make this feel like a "blower" motor at the hit of the throttle.
 
#20 ·
Jim, Mark has dynoed too many combinations to be wrong, so the ONLY question is how much do we lose. We may find out tomorrow what a race-prepped Qjet costs us. If it doesn't dent the TQ curve much, I'd be happy. I only hope it doesnt defeat the ultra care in the heads and such that he took. The dyno will tell us soon! ( ps, it likely isnt as much as my low rise tripower, which he reckoned is worth a loss of 50hp, same as the Ls "pancake" mani)

Darren, while I wanted to use a Straub optimized cam, I wasnt going to question the builder's "recipe" on his 454 builds. So its the 228/238 ISKY HR and we did elect to leave it on 111 LSA and not a 107 LSA for idle quality, Qjet compatibility and long highway runs i.e, a bit of mpg if allowed . The heads are done to optimize that mid lift (.570) flow. And the heads came out MINT on the flow bench, although Mark had to work two of the good ports a bit more than anticipated.
 
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#21 ·
Refresh me, what intake will the motor have? I think you'll be surprised at how well a good Qjet will perform. Yes, Holley design is easier to mod and in wheels up drag racing, circle track and road racing the center hung float design and fuel bowl capacity of a Holley is a lot better. That said, one only needs to look at Stock and Super Stock cars from the muscle car era and keep in mind, except for the factory solid lifter cars (and the early Chevy 396 cars and anything that wasn't a dual quad or tripower ?) every thing else GM (Chevy, Pontiac, Buick and Olds) ran a Qjet.
 
#22 ·
Joe, I chose the dual flange GMPP oval port intake, so I can run a Qjet mainly. One of my parents worked at RPD, and it IS a 325hp car , we think.
 
#23 ·
PS having said that, there is NO WAY the Qjet will keep up with my done 850 Holley at the track. Not even a contest. One has two big fuel bowls, one has ONE medium sized one. It would take a pretty sophisticated pusher type fuel system for the Qjet to get the BSFC to max out Mark's engine to its potential. Again, Qjet is just for long hauls, which is primary duty for this horse. I already have two feed lines and two spacers made up, one Qjet, one big holley. :)

600HP from a Qjet requires a race fuel system, something I will not need, nor want due to the drone of an electric pump. Its a resto by gosh! ;) Which hopefully pulls a little " walk softly and carry a big stick" at the track once in a while.

The Holley is for the track, MAX EFFORT, HENCE my original question on boosters. I know my big Holley will support near 120 mph with nothing more than a Carter NASCAR mech pump. ( 12.24@118.75 to be precise), and it seems like it wont gain ET, in any meaningful way, by replacing the downlegs it has now according to y'all.

PS, I am not familiar with dyno pulls, never having experienced one, but I suspect you dont hold WOT for 10-12 seconds like you do at the track. Therefore, whatever the Qjet "prints" on the dyno sheet, that's not how it'd carry for another 5-8 seconds, to wit, its not how it'd perform on a full 1/4 mile run I'd guess. Not without the aforementioned "pusher" high volume, low pressure fuel system, which wont happen here. Not yet anyway.

THNX FELLAS!
 
#24 ·
Gene,
Surprised you're not flying out to CO and witness this "birth" and it's dyno pulls.
I know I'd be there for sure after spending $$$ for a new engine.
 
#28 ·
Mark dont do LS engine Bill! ;) I kid.... I know, my kid's schedule and his need to get his life rolling trumped it, what can I say. The new born rat spun a 28 lbs flywheel ( not typically used on dyno runs) to 600FtLbs/603 HP at 6100 rpm yesterday afternoon, in really crappy air, with Marks 850 Holley set up identical to mine ( not the typical 1000cfm AED dyno mule he uses) .

Today we'll see if the new born can muster 600 ft lbs and maybe 580-HP with a Harold Bettis -prepped race Qjet. Are THOSE boosters annular? :D

Gene, a little off topic, but which one of Marks engines did you decide on? Looking back in past posts, can't find that info. What's the specs?
Darren , this is identical to the engine Mark featured in a youtube video months back, "street /strip 467" . 9.85:1 , HR, ported and flowed, Mahle/GM rods and I beleive a Scat crank in this one. We elected to keep LSA wide at 111, so it'll definitely idle like a oem 350 hp car. no "thumpr" here, Only in FT LBS! .

"Smooth" as Mark called it. Hey, I'll buy that for $1 or even $10,000!
 

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#25 ·
Was just out there last week to move son #1 to DEN and hoped it would all come together but...timing was off. We were both bummed out about it. Heck, I wanted to drive the bullet home, I hate the thought of shipping it , almost more critical than simply watching its birth. Mostly I wanted to, and still hope to, make Mark's personal acquaintance. He spent a good chunk of his life on this build, I'd like to at the least shake the man's hand out of deep respect for that is all. I have a feeling we'll be visiting CO numerous times over the year, once for a ski trip which I cant do ( Airborne knees) , so hope to slip down to Colorado Springs to say HI without disrupting his workflow! I'd like to buy the man lunch.

Until then, I promised Mark I wouldn't hog tie this beast at the track with a Qjet, nor would I put that shiny but -50HP tripower back on. So I have to follow orders until I do make his acquaintance. That fella knows more about engines and track racing than most anyone I've met, or should I say have yet to meet!

I dont covet, as a matter of "religion", but I said to myself, what ten years ago when we "found" Vortecpro, or he found us....when I had a phone con with him. .... someday I have to have this man build a rat for me. That day is here! and for that alone, I am very grateful.
 
#26 ·
I can't comment on modern fuel systems to support running a QJet. My only experience with a dedicated Qjet drag car was '67 Chevelle, SSIA back in the 70's. Car ran low 11's, mph in the 117-118 range?? Basically stock 396/325 with solid roller, single plane intake (Tarantula with the twisted runners, remember those??), 5.13 gear and 13x31" Goodyears It did have electric fuel pump. (I remember that much)
 
#27 ·
Thats getting it on! I could set out on a mission to get the Qjet to run at the track, but truly, its for OTR running and full dress. Pretty much if there are slicks on the car, it'l be running my race Holley. It is a horrible pig OTR tho, you can t squeeze more than 10 out of it. No matter how easy you drive it. It'll be sightly worse with this 467 over the 427. But the ol Holley should lite 'em up at will. Any speed any gear. At least it used to with the 427 when dialed in even with downlegs.

I'll see what it does before I tinker anymore with it or try a annular carb.
 
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#29 ·
Hey Bill, Bill Waters made me do it. I got jealous when he put his new 475 together! Actually, mr 4 speed as my witness, I've spoken about one of Mark's "smooth bruisers" for many now ( likely when I last freshened the 427 in 2013) . Something that wont mind the 4 gear 331 oem setup so much. We'll see next year at the MCC show, Lord willin'!
 
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#31 ·
We'll see this afternoon Joe. First Mark wants to try his stagger jetted race-prepped 850, as the air is so bad now he feels that it will pick up over the lean jetted 850 run yesterday. ( oddly that one is set up exactly like mine, 77 pri 80 sec - so I have an IDENTICAl carb here) . And then he'll bolt a race-prepped ( cant be run on street he says) Qjet and see what it does. We'll start a new thread about Holley V Qjet - at a mile high! I hope he has a moment to make a video for all to share.

STREET TIRES!? Ha, I already know the Holley will ANNIHILATE street tires at any rpm. It did with the 427. ( the tripower couldnt) If you see slicks on the car, the Holley is doing fuel duty! Street tires = Qjet. Which will still likely "smoke 'em at will".
 
#32 ·
Gene...you need to join the 21st century ;) :waving:

I have recently and will never look back.
OMG...Adjust A/F, initial & total timing, shift points, data log, and much much more just from the touch of a few buttons. On the fly if necessary.
Can't believe it's sooo freakin' easy.

NOW I want to do a max effort, big inch, twin spooled LS and drop it into a Chevelle.
Still in my blood, I'm guessing...

 
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