Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine> Quadrajet to Holley
User Name
lost password?   |   register now

Thread: Quadrajet to Holley Reply to Thread
Send Trackbacks to (Separate multiple URLs with spaces) :

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Additional Options
Miscellaneous Options

Topic Review (Newest First)
08-26-2012 05:46 PM
handy7rick I would not use more than a 2000 rpm rated stall for a daily driver unless the cam in the car has a power band that starts at a higher rpm than that and even if the power band starts at 2500 rpm ,you can still manage well and be much more streetable with the 2000 stall if its a true 2000 stall(usually a B and M make) before the car engages the wheels .
08-22-2012 05:28 PM
Q Jet

For me, the QuadraJet's were great carbs back in the day. When they work, they work great. When you step on the gas, and it's like flushing a toilet, throw your Quadratoilet away.
As for what to replace it with, there are a lot of options out there. Holley's are awesome, if you know what you are doing. Edelbrock's are a lot easier to set up, and the price is similar to a holley. You can run an adapter on your intake manifold, but if you look on Ebay, you can find a used Edelbrock (or Holley) manifold for about 2/3rds the price of new ones. Look for rebuilt carbs on Ebay too. If you don't dare swap the manifold on your own, (probably because of the distributor) it would be cheap to do at a local garage.
08-21-2012 11:26 PM
Originally Posted by nitsuj View Post
I have a mild Chevy 350 in a 28 Nash street rod. The carb on it is an OEM Carter built quadrajet. Performance is lacking. It runs ok, but I know it should run better. A trusted friend reccomended I scrap the quadrajet and put on a Holley 650 with mechanical secondaries. The car has sat for a while so I had planned to rebuild the carb anyhow, but if I'm better off with the Holley, then I'll go that direction. My question is, is it a straight swap? Will the Holley fit on the same manifold (it's and Edlebrock manifold)? Is it as simple as going to the auto parts store buying a carb and bring it home and slapping it on? (Then fine tuning I'm sure) if so, which Holley to I want they seem to offer a million.

It may seem like a silly question to a lot of you more knowledgeable folks. I've been a motorcycle mechanic my whole life and have some boat engine experience, I have the mechanical abilities and the tools, I just have very little experience with carbureted small block Chevy engines.
An aluminum factory Chevy Q-jet intake and the Q-jet you already have is the cheapest and IMO best way to go about it. If weight isn't a concern, use the factory cast iron unit. You can pick one up for >$20. Trade or sell the Vic Jr. to someone who needs it, or save it for another engine build.
08-21-2012 07:55 PM
Stall converter

Originally Posted by 71malibu View Post
what stall converter would you recommend for a 71 chevelle th350 with a crate 350/350 but used as a daily driver?
Checkout Summit Racing or Jegs for a converter in the 2400-2800 range. B&M, Hugh's or TCI. Edelbrock 600 cfm carburetor is fine. A Edelbrock Performer RPM is much better.
08-21-2012 05:07 PM
GMCTRUCKS Ebay is always having Q-Jets you might find one from your year and rebuilt it I had one on my 70 GTO she ran super never had a problem with it.
08-21-2012 02:43 PM
RLDSL Go with an Edelbrock/ AFB carb for sure. I cant count the number of those things Ive planted on small blocks over the years. they will drive great out of the box , but if you want to fidget a bit you can get great fuel mileage AND great power out of the same carb. I wouldnt own a holly on a street vehicle too many headaches If you still had the stock manifold, it might be worth the fuss going through the q jet but for as high as the learning curve is on those things, youd be cash and sanity ahead to just get an Edelbrock.

It sounds like you are running an open single plane manifold. If you want it to behave better on the street and not waste fuel , if it didnt come with a removable divider plate to slide in there ( if it did, go find the thing and slide it in ), grab a chunk of 1/4" aluminum plate and poke wet rags down the runners to catck filings, then grind out a notch front and rear dead center just wide enough to hold the plate tight if you slide it down in there, then cut the plate to fit the contour of the inside and grind a little into the bottom to keep it from wandering . clean it all up and set that thing in before mounting your new carb and you will improve your low end street performance and fuel mileage
08-17-2012 06:11 PM
jebo Just a thought! I love Quardajets and believe in them in all ways. I've worked with them for years but they do have few chacteristics that are common and fixable like the two swege plugs leaking on the throttle plate whice throws your emissions through the roof and an idel that is eratic. I have a 1934 Ford with a chevy 350 in place I tried all kinds of setups. Out of the blue I placed a old Carter AFB on it and it runs like a stripped ape. Edlebrock makes a carb that is identical to it. Edlebrock 600 I believe. Pretty cheap last time i checked and its polished.
08-16-2012 11:33 AM
Just put a $250.00 Edlebrock 4 barrel on it a be

If your car is a driver, (not a drag car) just put a $250.00 Edlebrock 4 barrel carburetor on it and be done with! Fast, Dependable, Simple and Low Cost. If your going to race the car, by all means go with the Holly and put up with the tuning issues.
08-15-2012 05:39 PM
Too Many Projects You've already heard enough about the virtues of the Qjet. You've also heard that the intake you have isn't the best for a street engine. I would start there. You don't want an open plenum intake on a street engine, especially a mild one. You are losing much low end torque and response. If that is the issue you're dealing with, find a performer or similar dual plane intake to try. If you're convinced to ditch the Carter, I second, third, fifth, whatever, endorse the Edelbrock over a Holley. Holley has name recognition with racers and that is about all they are good for. They are finicky on a street engine and can work fine in the temp/humidity conditions of one day and run like crap the next when the weather changes. I was a die-hard Holley man for many years until I bought a Camaro with a 600 vacuum secondary on a 350. The carb just plain works on any day I chose to drive the car. No fuss, no screwing around. As for mechanical secondaries, they are for manual trans cars. You want the vacuum for an automatic. Mechanical carbs will hesitate, or bog, horribly when you mash the throttle at low rpm, because everything opens instantly. The vacuum drops to near zero and the intake is flooded with raw fuel. Not the best formula for performance. Unless you like playing with the throttle to keep the engine running cold, the electric choke is a must also.
As for the Cater, if you have run oxygenated fuel in the past, the carb is full of corn residue. It needs to be completely disassembled, soaked and cleaned properly. Only use non-oxy fuel in a carburator. They were never built for the toxic environment of alchohol. Do a web search for pics of aluminum body carbs that have been destroyed by corn based fuel when allowed to sit over the winter. It's shocking to see what that crap will do.
08-15-2012 03:44 PM
Originally Posted by 2000jack View Post
Buy an Edelbrock, take it out the box and drive down the road. I have had 3 new Holley carbs in 5 years on my '29 and I bought a Edelbrock for my '27 it ran so good I switched it with the '29 now the '27 runs poor. i used Holley back in the 60's. Loved them then, even had a three barrel on a GTO, not now. Oh yea, page 19 of October's Hot Rod magazine has a picture of my car!
They're dirt simple and they work well. The AVS is even better than the AFB but they're both great for engines that aren't too radical (I have one on a 2.3l with a 244 cam and it was a bit of a PITA to get it tuned right off idle)..
08-15-2012 01:56 PM

holley carbs are great but so are qjets. i'd suggest getting the qjet rebuilt by some reputable rebuilder and be different. the hot rod magazines will have advertisers who rebuild carbs that will probably have a warranty too.
be different, it what hot rodding is about.

08-15-2012 01:25 PM
Big Bubba
Quadrajet to Holley

Thanks for the education. I will file that away in the memory bank for future use.
08-15-2012 01:24 PM
2000jack Buy an Edelbrock, take it out the box and drive down the road. I have had 3 new Holley carbs in 5 years on my '29 and I bought a Edelbrock for my '27 it ran so good I switched it with the '29 now the '27 runs poor. i used Holley back in the 60's. Loved them then, even had a three barrel on a GTO, not now. Oh yea, page 19 of October's Hot Rod magazine has a picture of my car!
08-15-2012 11:21 AM
Silver Surfer
Originally Posted by Big Bubba View Post
Wasn't Quadra Jet carbs built by Rochester instead of Carter?:
Rochester designed and made them. During the muscle car craze they were unable to keep up with production demands and thus GM contracted Carter to make them for a few years. Those carbs say Rochester and say manufactured by Carter. I believe the casting numbers are a different sequence too.
08-15-2012 11:04 AM
Originally Posted by Big Bubba View Post
Wasn't Quadra Jet carbs built by Rochester instead of Carter?:
Yes, it was the GM 4bbl starting in around 1968 or so, replacing the old 4gc. But since then everybody from Weber to who-knows-who has been making clones, because a lot of people liked the design. The small primaries make for great off-idle response, and the huge secondaries are at least tunable to minimize the instant-lean condition (bog) you get if they flop open too fast.

Carter did make the Thermo-quad, which is a spreadbore and has mechanical secondaries with an extra upper set of valves that open under vacuum demand, like a qjet (and Edelbrocks, which are modified Carter AFBs). On vacuum-operated Holleys, however, the vacuum opens the actual secondary butterflies.
This thread has more than 15 replies. Click here to review the whole thread.

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -6. The time now is 02:57 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.