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another carb question

Discussion in 'Chevy Trucks' started by Sawbones, Jul 28, 2001.

  1. Sawbones

    Sawbones Junior Member
    Messages: 14

    I have a mild 350 in my GMC and need a carb. I am confused about which brand to get. Its a '77 with a 203 transfer case so I would like fuel economy but want to be able to adjust needles,jets,mixture,idle etc easily when i need the power. Quadrajets have been suggested but i read so much bad stuff on them im not sure what to think. I have no expeirence with carter, holly or edlebrock and was wondering if anyone could give me some pros and or cons.
    thx.
     
  2. 75

    75 PlowSite.com Addict
    Messages: 1,382

    Just curious, what "bad stuff" have you read on Quadrajets? Is it mostly hearsay or documented info?

    "Rochester Carburetors" by Doug Roe (published by HP Books) would be a good book to read, obviously it's written from a pro-Q jet perspective but has lots of information on on Q-jet operation, service & tuning. Another good volume to look at is "Holley Carburetors & Manifolds", also published by HP Books.

    As for economy vs power, the small primaries/big secondaries on the "Quad" offer a good compromise between the two.

    Without major engine mods, I don't think that dumping more fuel in via the carb is going to make a huge amount of difference in power output, particularly if you have a fairly mild 350 (sounds similar to what I have)

    If you already have a Quad in good condition, I don't think you'll go wrong using it. If you have to buy a carb anyway, Holley & Carter make good units too.

    One pitfall to avoid is simply bolting on too much carburetion. As mentioned in another "carb" thread, 600 cfm is just about ideal for any street-driven 350.
     
  3. Sawbones

    Sawbones Junior Member
    Messages: 14

    Where can i find those books? By mild 350 I mean shaved heads to 9:1, 214/224 cam, .445/465 valve lift, Performer intake, Hooker headers/exhaust. I have always been told by carb shop guys that quads are one of the best. I was just wondering why all the shade tree guys swearby holly and edelbrock and come up with phrases like "dribblejet" and "quadrajunk". I had a stock replacement 600cfm holly a while ago and could never get it working right. All I have is the engine now and I need a carb. I've found a few rebuilt quads on e-bay and summit and would like your opinion on them vs others.
    thx.
     
  4. Sawbones

    Sawbones Junior Member
    Messages: 14

    Also, there are 50 million types of rochesters. Do these books break down serial #'s? And what's the difference b/w divorced, electric, and manual chokes performance wise?
    thx for the info.
     
  5. 75

    75 PlowSite.com Addict
    Messages: 1,382

    I've had my books for a number of years now, but I got them at a mainstream bookstore. Not sure what large chains you have down in your neck of the woods (Canada's so similar, yet different in subtle ways!) but if they aren't on the shelf ordering them should not present a problem.

    I also believe that Motorbooks International has similar titles in their line. Some performance shops may carry these types of books as well.

    There isn't a serial # breakdown in the book I have (with the 50 million units you mentioned, that would be a book in itself!)

    As far as the different types of choke setups, performance wise there shouldn't be much difference since what changes is the actuating mechanism - the choke butterfly works the same way in all the different models. Only way I can see an effect on performance would be if the choke is out of adjustment.

    Divorced choke has the thermostatic coil mounted on the intake manifold with a rod connecting it to the choke linkage. Electric choke has everything mounted right on the carb, powered off the electrical system. Manual choke is the simplest, but all 3 systems work fine when properly set up. Electric would be, IMO, the easiest to adapt to an engine the carb wasn't originally installed on since it's just a matter of getting power to the choke coil.