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750 cfm Rochester???

Discussion in 'The Garage' started by pismorat, Oct 12, 2003.

  1. pismorat

    pismorat 1/2 ton status

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    My buddy gave me what he said is a newly rebuilt 750 cfm quadrajet for free. I am running the stock carb with all the SMOG ports on it, and am wanting to put this one on and free my truck of all the SMOG equipment and get more power. Are some Rochesters really 750cfm? and would this be worth it? My stock carb needs to be rebiult anyways, so its one or the other. /forums/images/graemlins/truck.gif
     
  2. Stroked72Blazer

    Stroked72Blazer 1/2 ton status

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    yes in fact they also made an 800 cfm version and now Edelbrock makes an 850. The rochester 800 can also be modified to flow more than 950cfm. I asume your stock carb is also a q-jet. If so you have nothing to loose by giving it a try. Chances are it wont be properly tuned for your motor so it probably wont run good without re-jetting and changing metering rods but you might get lucky.
     
  3. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Q-Jets came from Rochester in 750 and 795cfm versions. Edelbrocks Performer RPM's are 850's.
     
  4. pismorat

    pismorat 1/2 ton status

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    What cfm should my stock Rochester Quadrajet be? /forums/images/graemlins/truck.gif
     
  5. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Either 750 or 795.
     
  6. Triaged

    Triaged 1/2 ton status

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    Most of the non smog Q-jets were 750cfm. Most of the newer electric choke Q-jets are 795cfm. I don't think you will see any diffenence in power in swapping and you won't pass smog with the other carb. You would be better off tuning your carb.
     
  7. pismorat

    pismorat 1/2 ton status

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    Sounds good, I am going to the Pamona Swap Meet this coming weekend, should I hold off on this free one and try to find an Edelbrock 850? What other carb(s) should I look for? What do you run? Thanks. /forums/images/graemlins/truck.gif
     
  8. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Going to a 850 won't gain you any power. Q-jets work alittle different than other carbs. They will only flow what the engine needs. Thats how GM gets away with the 795's on the little 305 SB. If your 406sb really has 400hp, then perhaps just the regular Performer Q-jet would be a wise choice. Or like Triaged said, a good tune/rebuild of your current carb.

    As for what I run- I just bought a Holley Truck Avenger 770 for my BB. I haven't had a chance to run it yet- My engine is still under contruction . Read some reviews on it, and it seems to out perform the q-jet in most areas. I'll see when the engine is running if thats true or not.
     

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