Which cam were you planning to use? I thought I saw somewhere you were going with the Isky H-roller 228/238.

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.

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.

I told that to the guy that dynoed my 421. I gained about 20hp with his dyno carb.
I was kinda disappointed.

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.

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.

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.

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. ( [email protected] 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!

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.

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.

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)

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.

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?

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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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'!

This will be interesting. Back to back in controlled environment, no changes but a carb, not the typical we changed intakes and bolted on XYZ carb, etc. Probably a cfm differential and maybe the way the secondaries open you might see some torque differential in midrange. Who knows. But if you come up anywhere within 20# torque, 20 HP difference, you almost won't know that on street tires.