Carburetor question
Thread Starter
Cruising
Joined: Aug 2020
Posts: 10
Likes: 0
Carburetor question
Hi all, I have a 71 roadster with stock 350 and running the original Rochester quadrajet. I am looking to upgrade the carb and wondered what people think? I would like something easy to tune and provides a bit more horsepower. I have upgraded intake manifold and require a spreadbore type carb.
Thanks
Thanks
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
The stock Q-Jet will outperfrom or equal any other carb for horsepower - you will not get more horsepower by switching carbs, unless there is something wrong with your stock carb. If there is, just fix it. 
Lars
Lars
Last edited by lars; Aug 31, 2020 at 04:50 PM.
Burning Brakes
Joined: Oct 2000
Posts: 878
Likes: 60
From: Minneapolis, MN USA
Funny - I just did the opposite. The previous owner had a Holley on the car, but fortunately retained the original Q-jet. I am switching back to the original Q-jet (rebuilt by Lars!) and am expecting better over-all performance. I have heard rumors that the Q-jet might be harder to tune, but we will find that out later, I really don't know. Hopefully I will finally get my car put back together this week and can drive it next weekend and report actual results!
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
I can provide you the dyno test data to show you what I'm talking about - I've posted it here on the Forum many times, so just e-mail me if you want to see it. Bottom line: Use whatever carb you are most comfortable with tuning. The carb setup and tuning is much more important than the brand, but the Edelbrock so-called "Performer" (cheap re-pop of the old obsolete Carter AFB) will get you a solid 15 hp power loss over a correctly set up 750 Q-Jet or a (good) 750 Holley. Holley makes several cheap carbs that are not "good." On a mild small block street car, you will not be able to install a carb that produces more power than a correctly set up and tuned Q-Jet. Any well-tuned carb will outperfrom a badly set up or faulty Q-Jet. It works the other way around, too. Fix what you have and run it.
Lars
Lars
Burning Brakes
Joined: Oct 2000
Posts: 878
Likes: 60
From: Minneapolis, MN USA
Send yours to Lars and ask him to do it. That's what I did. He is known to do a great job and has fast service. I hope to finally experience mine running this weekend!
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Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
He lives around Denver. Care to take a trip south? 
If nothing else, you can contact him via e-mail ONLY at V8FastCars@msn.com to explain what you have (in detail with info on any prior rebuilds the carb has had), info about the engine. trans. rear gear & tires, and how you intend to use the vehicle. He can give you advice and maybe provide detail on the Canada/US 'thing'.
Whatever direction you take, the info he will provide will be very useful to you...even if you cannot arrange for his servicesw.
If nothing else, you can contact him via e-mail ONLY at V8FastCars@msn.com to explain what you have (in detail with info on any prior rebuilds the carb has had), info about the engine. trans. rear gear & tires, and how you intend to use the vehicle. He can give you advice and maybe provide detail on the Canada/US 'thing'.
Whatever direction you take, the info he will provide will be very useful to you...even if you cannot arrange for his servicesw.
Is my vette stock?? HAHA
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From: Im not allowed to tell you
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If its all original and in good shape you can do it. Buy the Cliff Ruggles book and a rebuild kit for the model you have from quadrajetparts.com or quadrajetpower.com. Theres a number stamped in the side to tell you the model. IF you have reservations about doing it, contact Lars. He may ask for a pic before you send it but it is money well spent if you havent rebuilt one before. And he will test it on his motor before sending it back to you. It just depends on how comfortable you are as a mechanic.
Safety Car
Joined: Jan 2004
Posts: 4,549
Likes: 343
From: Glastonbury CT
If you just change the basics and take your time you should have no problems but to dial it in i would suggest Lars Also if you do not have a mechanical back ground send it to Lars. This is the heart beat of your motor! I just did two for my self and it takes time and those kits they sell are not like the GM originals some items are there and some are not!