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carb size for a small block

Discussion in 'The Garage' started by Tshane, Jul 31, 2003.

  1. Tshane

    Tshane 1/2 ton status

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    I heard from people to run 600cfm for small block thats all you'll ever see but i also heard run 750cfm?????????????? i was wondering what you guys think about it and WHY you think u should run one or the other. /forums/images/graemlins/1zhelp.gif
     
  2. sled_dog

    sled_dog 1 ton status

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    you are talking a 383 with other performance mods. a 700 or 750 wouldn't be out of the question for best performance on top of that. I know a friend of mine runs a 750 on top of a built 350(stock bore and stroke).
     
  3. Beast388

    Beast388 1/2 ton status

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    A stock 265cid in a '55 chevy isn't going to need nearly the carb that an LT1 350cid in a Camaro does....so saying one carb size fits all is a little naive.

    I started with a 650 on my engine, but I felt that it had more ponies in her, so I tried a 750 and haven't looked back. /forums/images/graemlins/thumb.gif
     
  4. chulisohombre

    chulisohombre 1/2 ton status

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    i run a 600 cfm on a mild built 350.but i have vette heads with 2.02 intake valves.so it can use probably a biger carb.
     
  5. rcpilot

    rcpilot 1/2 ton status

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    According to Holley Carb book a stock 350 only flows in the neighborhood of 300-350 cfm... a stock engine to mild stock will do fine with a 600 or 650.. use a 750 and you'll most likely be de-tuning it in order to get the best performance. My $.02
     
  6. sled_dog

    sled_dog 1 ton status

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    see his other thread hes building a fairly worked up 383 so its definetally more than a mild 350.
     
  7. bablazer73

    bablazer73 1/2 ton status

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    CFM is calculated by engine cubes x rpm turned. I have a chart I use as a guide line. a 468 is going to need a minimum of 850 cfm to make power at 6,000 rpm. 750 to go to 5,000 rpm. so depending on what rpm your engine is designed and going to make power in, will decide what carb to use. This chart is based on an engine running 100% volumemetric effiency. Which most NON dyno tuned engines will not get! It is better to under carb than over. The larger the cfm, the less throttle responce you will have. do you really know what rpm your gonna spin this too??
     
  8. leadfoot067

    leadfoot067 1/2 ton status

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    edlebrock q-jet...performer rpm model......should work very well for ya...even though it says its 850 cfm..it has small primarys so throttle response is good still... /forums/images/graemlins/thumb.gif i love mine..works killer off road...see naches pics in my link,had the blaz layed over on its side pretty good and the carb would still sit and idle /forums/images/graemlins/thumb.gif
     

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