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HippieCustoms
03-12-2004, 08:18 AM
Ok, here is what I have. 91 5.7, the engine ran fine but I wanted more power (who doesn't). I ported the stock 217 heads, replaced the performer intake with a taller cast iron gm dual plane intake, installed a comp cams xtreme marine cam, lifter and spring set, 12-236-3, new thunderbolt 4 ingnition module for a magnum, new merc fuel pump for a magnum, and stainless marine exhaust for the small block. now, boat runs great, sort of, it is leaning out a bit on the big end. I am sure the carb is in need of jetting. the problem is I have only worked on Holleys, and don't know the first thing about a Qjet. I have also heard nightmares about inexperienced people really messing one up if they didn't know what they were doing. So any advice on how to figure this carb out would be greatly appreciated. I don't want to just drop the money on a holley if I can make this one work...Thnks Hippie

BUIZILLA
03-12-2004, 09:10 AM
Personally, I like Q-jets. A lot....
with your combo, I would richen the primary jet size 3 numbers, and drop the secondary metering rod number 1 size, and go from there. The smaller the tip size on the rods, the richer the circuit.

J :lookaroun

HippieCustoms
03-12-2004, 07:49 PM
Personally, I like Q-jets. A lot....
with your combo, I would richen the primary jet size 3 numbers, and drop the secondary metering rod number 1 size, and go from there. The smaller the tip size on the rods, the richer the circuit.

J :lookaroun
Ok, I am good with that, except, I have never had one open and do not know where these parts are, or what I have to take apart to get to them..
I know I must sound like a beginner, but when it comes to these carbs, I really am........Is there some on line info somewhere that will tell me more? Pics, what gaskets I should buy before I start, etc.?. Thanks still.
Hippie.

Dennis Moore
03-12-2004, 09:16 PM
I don't want to SPAM here but my book has some good info on Quadrajet jetting.
The Quadrajet secondaries are the easiest jet change you will ever make. You don't even have to shut off the engine! The secondary air valve lifts a hanger with metering rods out of the main jets when they open. Remove the hanger and install metering rods with smaller tips.
Dennis Moore
www.mooreperformance.org

Walt. H.
03-13-2004, 02:17 AM
Dennis,

Welcome aboard here as a member! :wavey:
I have your book on Marine small block chevy's and i've read it from cover to cover a few times over the past year and a half, plus I have as many marker in between the pages as a priest has in a bible. :eek!: I've been turning screws for over 40 yr's 28 for a living, now back as a hobby and I still learned plenty from your book! So yes I do recommend it to all! :yes:

Now that my boat is back together i'll be doing some of your milder performance up grades. I had to replace my stock cracked OEM exh manifolds the season before, I sure wish I knew about your lighter aluminum manifolds back then. But hopefully i'll make some more room on the shop shelves for those OEM iron manifold I have in the near future.

Lightening the load is free H/P too,

BestRegards,

Walt

harbormaster
03-13-2004, 09:35 AM
Welcome aboard Dennis. Thanks for the reply. I heard Keith is bringing back some manifolds from California in his luggage.

HippieCustoms
03-16-2004, 10:20 AM
Thanks Dennis, and everyone else. I have pulled the rods from my carb, they are CL . Now I cannot find a good chart anywhere to tell me which I should go to next. By the way, I will be getting you book Dennis. Thanks again with anymore help you guys can give.....Martin

BUIZILLA
03-16-2004, 11:13 AM
There is a fantastic book, author escapes me, on Qjets. Get it. For my drag race Qjets, I use John Osborne in Rineyville, KY. He KNOWS his stuff.

J

Murphy
03-16-2004, 01:12 PM
There are a lot of Q-jets in boats on this site. Let's see if we can put together a comprehensive resource list... books, vendors, tips, etc. to help ourselves out. Maybe for practical purposes this could eventually be moved to the technical section.

Thanks

Murph

Dennis Moore
03-16-2004, 10:10 PM
Thanks guys for all the nice words. I'm pretty busy but I'll try and respond as much as I can. Met Keith in Pasadena and had lunch with him. He is packing manifolds for the plane ride back.
Sincerely
Dennis Moore

HippieCustoms
03-17-2004, 03:50 PM
Ok, I found some jets and rods localy. Actually found a carb that had what I think I need. Hopfully you guys can tell me.
What I have in the carb now is what looks like primary jet #69 and primary rod 41. Secondary rod is a CL.
The other parts I have are primary jet 71C and primary rod 52, with secondary rod DR.

Now I am willing to just install these parts and try it, but, the primary rod I have now is smaller than the one that came with the bigger jet. It is also alittle longer. So , should I just change the jet and keep my rod or change them both? The valve over the spring that the primary rods hang on are completely different from one carb to the other. just thought I would throw that in...Ya'll please let me know...Thanks, Martin.

Rootsy
03-17-2004, 08:51 PM
Hippie,

give summitracing.com a pull up... Edelbrock has tuning kits for quadrajets available in several different varieties... they are reasonable and summit is about the lowest cost you'll find short of wholesale... shipping is johnny on the spot too...

Jim,

do you know of Joe Scott? he's the Northeast Q-jet guru... he does some mind boggling things with these pieces... he aslo has one helluva quick SS pickup he campaigns in NHRA...

BUIZILLA
03-17-2004, 09:46 PM
Rootsy, I don't know of Joe Scott. All us Buick guys use either Val Hedworth or John Osborne.

I'm gonna look in my car trailer tomorrow for my Qjet info, it's buried in a cabinet somewhere...I gotta load a car tomorrow for this weekends Daytona show, so i'll dig in the drawers. I wonder what Pete Biondo's Qjet looks like after last weekends head-on crash into the tree's at OSW when his brakes failed ?? :eek: :eek: :frown:

J

Rootsy
03-17-2004, 10:12 PM
OUCH... so much for that GT car :rolleyes:

this combustion chamber rule change should shake up S/S this year... Maple Grove National Open is next month... we are considering dropping to SS/JA to see if we can gnab that class record or not... it was set at 10.02 by a fuelie car... gonna be close... Barton seems to think the combustion chamber unshrouding should be worth a 10th so a high 80 low 90 should be doable with the extra few 100 lbs... should be interesting...

Joe Scott does a lot of the Q-jets for the Div 1 guys...

BUIZILLA
03-18-2004, 06:32 AM
Rootsy, Pete was in his 69 Camaro stocker... OSW ran 4 pairs before someone discovered his car was on FIRE, buried in the tree's, typical OSW tactics.

J