Quadrajet vs Edelbrock?

Discussion in 'Engine Topic' started by smallblockchev, Jan 23, 2016.

  1. rocket dawg

    rocket dawg Veteran Member

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    This is off topic slightly, Off roading or climbing steep hills with a Q-jet on my 79 short box lifted 4X4 chevy ( 400 sbc) and the engine would die 3/4 ths the way up the hill. Put a Holley 650 on and problem cured. Been a Holley guy ever since---Are they perfect? no, in fact the Q-jet had less maintenance in a daily driver. But Holleys are so easy to work with that its worth it to me to run Holley.. Currently a 750 Holley on my 406 in the 78 Trans Am .
     
  2. loyal guardian

    loyal guardian Veteran Member

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    not a fan of holley. my whole family had eddy's. now not sayin much for family choice but these guys drove and tuned stuff no problem, these are the guys that drove funny cars and top fuel nitro cars almost all their lifes. "gone with the wind", "too much" all them. so when they use a part on their personal cars its for a good reason. so ima stick with eddy
     
  3. marx3

    marx3 Veteran Member

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    Most Qjets do. Bushings are 4$ a pair and all it takes is a drill bit ( dont remember the size ) and some Loctite.
    It takes about 15 minutes to install them. Really easy.
     
  4. shad_van

    shad_van Veteran Member

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    Cliff Ruggles offers a DIY kit for the throttle shaft bushings. also check the secondary air valve shaft in the top of the carb. in a Q-jet that has been beat on, they can develop a sticking problem. there is also a plastic cam that is used to lift the secondary metering rods. it is almost always worn out on all the Q-jets I have ever seen. I believe all the parts are available through Cliff shop. and they are great to work with.

    I have never had a problem with Edelbrock Performers having fuel control problems. usually when they are having fuel control problems, it is because to much fuel pressure or needle and seat problems. If you are at 5-7psi at the carb, then I would look at the needle and seat. have seen some Needle and seat assemblies that were absolute garbage, mainly in the cheap parts store brand rebuild kits. the biggest problem is the tip of the needle is not strait point, or canted to the side or it is oblong shape and wont seal the hole in the seat assembly. I use a Mighty Vac vacuum gauge hooked to the old piece of fuel line to test the needle and seats on all the carbs I rebuild. it should hold a vacuum if the needle is seating properly you can also use it to test if it will hold pressure by using a air compressor dialed way down to 5-7psi and lifting up on the float. it should seat the needle in the seat and cut off the air flowing out. I prefer the brand name needle and seats form Holley or Edelbrock and the kits from Cliffs for a Q-Jet. also a lot of the cheap kits don't have parts that are ethanol compatible. so they were out faster of the rubber hardens up. this is mainly with power valves and accelerator pumps. the current name brand kits form edelbrock and holley work fine with ethanol blended fuels. I believe the kits from Cliffs also feature ethanol compatible parts.

    I know the modern Holleys have blow out protection in them. however the ones on my old boat did not, but even with the blow out protection, they still leak, and you can only tighten the screws so much before you strip the threads on the base. I have not tried any of the Holley clones like Demon or Barry Grant. but I would assume they would have the same problems if where the gaskets are below the fuel level. that is the one thing I really like about Q-jets and AFB/Edelbrock Performers.
     
    Last edited: Jan 24, 2016
  5. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

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    My $.02...I have an Eddy on my 383 street car. Great manners, and don't have to mess with it for weather conditions. The way a car responds I beleive is soley with the owner and how he feels it and drives it. Perhaps a racer guy would think my car runs like crap. My spark plugs tell me otherwise. If there were 15 carbs to chose from...I think you'd have 15 different answers. Good luck ewither way.
     
  6. marx3

    marx3 Veteran Member

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    Don't mean to start an argument, but I think anyone would agree that a perfectly tuned carb giving the engine flawless, seamless response and transition between circuits, feels just like that: perfect.
    My own mild 350 feels and runs like it was fuel injected, because the carb and timing is perfectly trimmed.
    I have driven a lot of cars, that were feeling less than perfect, but the owner was happy, because he/she had never had the engine running any better.
    I believe you are right about the 15 carbs though, or more 15 different guys.
    I remember one car, I think it was an old Buick, were the owner felt it ran really good. It was not hard to start, it did not bog and die when floored, it idled reasonably etc. he thought it was running great, for an old carbureted car.
    Actually the car was sluggish and felt held back at any rpm and throttle angle. After a thorough carb tune and getting the ignition right, the car must have picked up 50 hp. The owner was very happy, needless to say.
     
    Last edited: Jan 25, 2016
  7. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

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    No argument...Seems though you restated what I meant to say about the owner and a car, but with a clear example. If the owner doesn't know any better, than he could be very happy with the car. A more experienced person may think the same car rides/drives like crap.
     
  8. marx3

    marx3 Veteran Member

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    Totally agree, but my point was, that everbody will agree, that a perfectly tuned carb feels perfect.
    That's why it is so important to get the right carb for your application.
    A Qjet with right jet size will be easy to fine-tune after it is put into service. The APT feature will make this possible.
     
  9. Rdobbs1977

    Rdobbs1977 Huge Guns N Roses Fan

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    I like Rochester quadrajets. Just tore one a part a few days ago and plan to rebuild here soon as a side project. If you've rebuilt a carb before (any make) you should'nt need a book. Me personally, I like Eddy carbs. They are not as complicated and I've never had any problems with them. A holley is more detailed and refined and I run one on a drag car only because eddy does not make a double pumper.
     
  10. dmoto

    dmoto New Member

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    I have all three, and all have their pros and cons. The main problem I have with quadrajets are the following; the leak fuel from the plugs on the bottom causing hard starting concerns and rich idle. Cliff performance sells a kit to fix them but you really need to know what you're doing before you drill out the bottom of those plugs. Second, I still haven't figure out how to change the power piston plastic collar and I'm afraid that they unseat after you assemble the carburetor. Last the transition to the secondaries is not as smooth as the others. Well I've had good luck with the Holleys, the prospect of fuel leaks is always there. As. for the Edelbrock they are ok.
    The real question is, whether to switch to the new fuel injection kits. While I have been against them for long time I'm leaning that way now. Holley has a new kit coming out that is priced less than $1,000 and doesn't require an oxygen sensor in the exhaust and a remote processor. Second a lot of companies are coming out now with electric fuel pumps that are easier to install and package.
     
    Last edited: Feb 2, 2016

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