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Post by MERSEY on Nov 1, 2015 16:29:25 GMT -5
One of my favourite websites... RacingJUNK.com also has some good technical info besides all of the great ads.....which were much more fun to check out before our CDN $ took a nose dive. There's always lots of discussion about carbs, tuning, jetting, etc and what's best for the particular combo we happen to be running or the one we might be planning to build. I breezed through this article and thought I'd post it here. There's lots of useful info and links contained within it. Here's the link to it: Selecting-the-Right-Carb-for-Your-Engine Mersey
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Post by brutus on Nov 1, 2015 18:52:58 GMT -5
This confirms what I have said all along...I need an 800CFm for the Chevelle. I am running a Demon 750 currently. I am told the Demon flows more like an 800 but I am not fully convinced.... Even though the article says not to mess with Jets, I will be upsizing the Jets a few times before spending $500+ on a new carb.....
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irock
Junior Member
Posts: 27
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Post by irock on Nov 1, 2015 22:26:58 GMT -5
I was struggling with a Holley 750cfm on my 355 a long time ago. Then I wrote to Chevy Hi-Performance magazine and got a response pointing to volumetric efficiency. That's when I realized I had too much carb for my use. Went to an Edelbrock Performer 650 with factory metering rods and jets and the car has never run better.
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Post by ponchokel on Nov 1, 2015 23:19:04 GMT -5
Yes Irock carb runs great:-) Don't fiddle with it...LOL..for big blocks I think 750 is minimum depending on build. Wild build would sure need 800CFM or more. Most small block chevs run just fine on a 600CfM. I like my 650 Thunder series Edelbrick.
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Post by ELKYBILL on Nov 1, 2015 23:26:12 GMT -5
Good info...I'm considering changing the carb on the Camino.
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Post by henrystoys on Nov 4, 2015 8:50:37 GMT -5
I have ran mostly GM Q Jets on my cars and in stock/ superstock class racing that is all we are allowed. The carb is self adjusting as far as air flow is concerned and some flow around 750CFM. Most people look at them as GM crap(Ford used them but I'm not sure about Mopar) but they propel cars to mid 9 seconds in the 1/4 mile. Super easy to work on and not a lot to adjust.
When using most formulas they are for WOT but how long do you drive at that position. 95% of the time we drive around 1600/ 2000RPM so you want the carb jetting to be optimal around those RPM's.
With any type of carb you set the primary's optimal for cruising and then set the secondary rods to get the most performance out of the engine.
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Post by ELKYBILL on Nov 4, 2015 19:48:35 GMT -5
I've always found the Q jet much more user friendly than a Holley.
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Post by brutus on Nov 4, 2015 20:05:29 GMT -5
Q-jets are ok, but I much prefer the Holley....I can screw it up in soooooooo many ways....
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Post by ELKYBILL on Nov 4, 2015 23:14:19 GMT -5
That's the problem...I've screwed up a lot of Holleys!
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Post by MERSEY on Nov 4, 2015 23:17:36 GMT -5
One thing about carbs......people always seem to be VERY loyal to whichever brand they are most familiar with or whichever they have found works best for them. I've found that some folks that like Holley's have a major dislike for Edelbrock's and vice versa. Also, most folks I've talked with think Q-Jets are great carbs BUT a beast to work on.....likely because they're not as common as they once were.
As my dad used to say "they're all good when they work"
Just my 2 cents worth.....
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Post by ELKYBILL on Nov 4, 2015 23:29:52 GMT -5
''they're all good when they work''...ain't that the truth...nothing more frustrating than a balky carb!!
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Post by brutus on Nov 5, 2015 10:03:14 GMT -5
I have had them all, Edelbricks, Quadra Pukes, Holleys, Demons, and now I am looking at going to a Quick Fuel. They make a 1000 CFM to fit my intake....YA BABY!!!!! This will be my TRACK carb!!! did I mention...YA BABY!!!!
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Post by ELKYBILL on Nov 5, 2015 10:50:45 GMT -5
Roger you have the same disease as me....SPENDIDUS..LOL!
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Post by ponchokel on Nov 9, 2015 17:26:23 GMT -5
I have a 800 CFM Edelbrick I may with? but kinda saving it for my some day Big Block?
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Post by brutus on Nov 9, 2015 17:45:02 GMT -5
Yah, I have a 750 Demon on the BB now, and I have a 850 Holley on the shelf as well. I had a 750 Edelbrick in stock until this spring but a street rod owner talked me into selling it to him...
I get tons more top end with the 850 on there. It would be interesting to see how much more there is in there with a 1000 on top....Yee Haw!!!
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