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Thread: Undecided between the 350 cfm or the 500 cfm Street Avenger.

  1. #1

    Default Undecided between the 350 cfm or the 500 cfm Street Avenger.

    Hello everyone, title says it all. I want to carb swap my 1979 AMC Spirit 258 cid inline-6 (factory equipped with a 2 barrel Carter BBD carb) and with the help of an adapter plate I'll be able to do so easily onto one of the two holley 2300 I mentioned: The 350 cfm 2 barrel Street Avenger or the 500 cfm 2 barrel Street Avenger.
    Which one between both should I choose? I want the best gas mileage without sacrificing power. And I fear the 500 cfm might outperform the 350 cfm performance-wise, but it'll fall short on better fuel economy, am I wrong? How big is the gap performance-wise and mileage-wise between the two carburetors?

    The car street driven and is my daily driver, max rev range 4800-5000 RPM, and it has just a few mods. A performance exhaust, headers, 2.5" exhaust pipe and a very mild aftermarket camshaft. Any light into my uncertainty on this matter will be greatly appreciated.
    Last edited by Danny Cabral; 02-01-2020 at 08:19 PM.

  2. #2
    Join Date
    Jan 2010
    Brisbane, Australia


    Ricardo:For me, you have a few options.
    As you have mentioned, 5000 RPM as max, then that would take the 500 cfm 2300 out.
    Your best option is the 350 cfm 2300.
    If you can find a model 2305 350 cfm or even a 500 cfm, both progressive secondary 2 barrels, built on the 2300 stud pattern, you could have the best of both worlds.
    Or you could go for a Weber 38 DGAS. Gary
    Last edited by Gaz64; 02-04-2020 at 05:24 AM.
    Regards, Gary

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