will this carb work?
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From: Williamson, NY
The 650 may be a little on the large side especially since it is a double pumper version. I think a 600cfm with vacuum secondaries would be a better choice, be more responsive and give you better fuel economy if you stay out of the secondaries. I used a cfm calculator for my 302 engine and the results came back at 350cfm. That is why I recommend the vacuum secondary carbs, since the primary side will be great for around town and when you need to pass just hit the gas and the secondaries will open and you will have all the power you need. Double pumpers have mechanical secondaries and are better suited for all out race applications and not fuel economy IMHO.
Jim
Jim
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From: Parma, MI
thats the thing I am not worried about fuel economy, I just want the most performance. I can get a 650 double pumper real cheap, and right now I have a edelbrock 600. Would I see a performance difference between these two carbs?
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From: Williamson, NY
It's hard to say w/o knowing the history of these carbs just how much difference you will see between them. If they both where new perfectly setup carbs the 650 would probably have higher top end at WOT, but the smaller CFM carb could have a quicker low end range due to the higher air velocity through the venturies. Where are you looking for performance improvements....or in other words how are you going to use your vehicle (is this a truck)?
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From: Parma, MI
yes its a 4x4. I guess looking for improvments top end. My edelbrock has good low end response but at high rpm's with the 4 barrel open it kinda falls on its face. almost has more power if I back off the throttle a little. And I can't stand that. Any thoughts? If I get the Holley I am going to buy one of those holley performance books, rebuild it, and dial it in.
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From: Williamson, NY
Originally Posted by ibleedblue1385
. almost has more power if I back off the throttle a little. And I can't stand that. Any thoughts?
Jim
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From: Parma, MI
Ok well its got an open 14" edelbrock cleaner, and bbk shorty headers into 2 1/2" duals w/flowmasters. So breathing is not the prob. unless you think I can get more air flow from a foam edelbrock filter? The motor is fresh with ported e7's. Complete MSD ignition. It feels like carb. But I could be wrong.
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From: Williamson, NY
What do you have for an intake manifold and cam? These two components also determine how well the engine will breath. You can have the best carb and exhaust on your truck, but if there is restrictive flow through the engine it will only breath as well as the restriction allows. Its like the old saying "the chain is only as strong as its weakest link".
Jim
Jim
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From: Florida
The cam will be your problem, your engine can only make power in the area that the cam allows.
Also on an overdrive transmission Holley doesn't recommend the double pumper series carbs, if you have an over drive.
Also on an overdrive transmission Holley doesn't recommend the double pumper series carbs, if you have an over drive.
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From: San Antonio, Texas
I have a 580 holley street avenger on my new 351w in my bronco and it runs like a bat outa hell.
Double pumpers are strickly for dragracing where you mash the gas and the secondaries open quickly so they need fuel as fast as the primaries do.
vaccum secondaries open slowly and they get there fuel as fast as they need it, as they are better for street, and much more drivability.
Double pumpers are strickly for dragracing where you mash the gas and the secondaries open quickly so they need fuel as fast as the primaries do.
vaccum secondaries open slowly and they get there fuel as fast as they need it, as they are better for street, and much more drivability.
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From: Troy,NY
Originally Posted by ibleedblue1385
Stock roller cam from a 92' stang.