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Discussion Starter · #1 ·
Guy's, need some advise...The current holley I have is a 650 DP I re jetted, different shooters, pink cam etc and I still can't get rid of the stummble out of the hole. I keep hearing DEMON is the way to go? Your thoughts? I have a 306 e303, windsor jr. heads ported polished, scorpion 1.6 RPM manifold. JE 10.1 pistons. 373 gear
 

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Quickfuel FTW

one of the best carbs i have ever had the chance to have on my car to be honest.

it was night and day from any other i had on it ever.
 

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Discussion Starter · #3 ·
Quickfuel FTW

one of the best carbs i have ever had the chance to have on my car to be honest.

it was night and day from any other i had on it ever.
What set up are you running it with? I also have a 150 shot I will be running though it.
 

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i no longer have that car, but it was a stock bottom end 302 with worked e7 heads, e303 cam, exhaust, etc 750dp. some small bolt ons here and there.

that carb flowed better than anything i have ever had, instant throttle response after having a holley 650 and even trying out a 750dp holley and it still stumbling on take off.
 

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Guy's, need some advise...The current holley I have is a 650 DP I re jetted, different shooters, pink cam etc and I still can't get rid of the stummble out of the hole. I keep hearing DEMON is the way to go? Your thoughts? I have a 306 e303, windsor jr. heads ported polished, scorpion 1.6 RPM manifold. JE 10.1 pistons. 373 gear
When you say out of the hole do you mean @ the drags on slicks,Or just driving normal from a stop? What are you running for a front shooter? You may also be lean on jets, what are you running?
 

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Discussion Starter · #6 ·
When you say out of the hole do you mean @ the drags on slicks,Or just driving normal from a stop? What are you running for a front shooter? You may also be lean on jets, what are you running?
Both on the slicks and driving on the streets. I have #28 and last night I tryed a 31..No difference, it bogged even more. In other words, sitting and from a idle to the floor, major hesitation the it kicks in? I re jetted ect...I keep hearing Holley's are crap?
 

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I have had both Holley and Demon and I can assure you if you are having problems tuning the Holley the Demons are harder to tune and have more driveability issues than a properly sized Holley. Your issue sounds like a tuning issue more than anything. Post up what jets you are running in the primary and secondary, where your mixture screws are at in # of turns from seated and people can start to point you in the right direction. Good luck with your project.

BTW I have run both 575 and 650 Demon DP carbs and had a much harder time dialing them in than either of my Holleys for driveabilty, idle quality and general street manners. They made good power and ran great at WOT.

If you do go with a Demon the 575 is all the larger one you will need. Due to Demons flow rating system which is different than Holleys the 575 is very comparable flow wise with a Holley 650 which is the proper size for your application unless you are turning lots of RPM or have High compression (11:1+)
 

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Discussion Starter · #8 ·
I have had both Holley and Demon and I can assure you if you are having problems tuning the Holley the Demons are harder to tune and have more driveability issues than a properly sized Holley. Your issue sounds like a tuning issue more than anything. Post up what jets you are running in the primary and secondary, where your mixture screws are at in # of turns from seated and people can start to point you in the right direction. Good luck with your project.

BTW I have run both 575 and 650 Demon DP carbs and had a much harder time dialing them in than either of my Holleys for driveabilty, idle quality and general street manners.

If you do go with a Demon the 575 is all the larger one you will need. Due to Demons flow rating system which is different than Holleys the 575 is very comparable flow wise with a Holley 650 which is the proper size for your application unless you are turning lots of RPM or have High compression (11:1+)
Jetting is 71 Primary, 67 secondary, 28 shooters, pink cam on #2 setting..Air flow I did not touch yet. Thanks
 

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I would recommend that you change your jetting for a 650 DP to 68 Primary and 74 Secondary. Also the mixture screws on the primary idle setting should be around 1 turn usually less to get the idle lean enough. This should get you in the ball park and you can tune from there. 28 squirters with pink cams front and rear should be fine. May even want to put them back on #1 hole and try the cams.

Also were are the throttle blades have you already set those properly? Hope this helps good luck.
 

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Discussion Starter · #10 ·
I would recommend that you change your jetting for a 650 DP to 68 Primary and 74 Secondary. Also the mixture screws on the primary idle setting should be around 1 turn usually less to get the idle lean enough. This should get you in the ball park and you can tune from there. 28 squirters with pink cams front and rear should be fine. May even want to put them back on #1 hole and try the cams.

Also were are the throttle blades have you already set those properly? Hope this helps good luck.
I will check all of what you are recommending tonight and let you know the results...I appreciate your advise.
 

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I think you would greatly benefit from finding a local carb-guy and having it dialed into your setup.
larger cc boosters may help off the line, but I think your best bet is to find an expert...
better to spend the money on experience than buy a new carb that may have similar tunning issues.

my $.02
good luck!
 

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I think you would greatly benefit from finding a local carb-guy and having it dialed into your setup.
larger cc boosters may help off the line, but I think your best bet is to find an expert...
better to spend the money on experience than buy a new carb that may have similar tunning issues.

my $.02
good luck!
agreed! sounds like the tuner and not the carb.
 

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Discussion Starter · #13 ·
I think you would greatly benefit from finding a local carb-guy and having it dialed into your setup.
larger cc boosters may help off the line, but I think your best bet is to find an expert...
better to spend the money on experience than buy a new carb that may have similar tunning issues.

my $.02
good luck!
Your $.02 is totally worth it! I was told the same thing by a good buddy. My buddy who owns www.mpgracingengines.com has a speed Demon 650 for 440 bucks, but I have herd now from you too I should get it the Holley dialed in by a pro.
 

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I think you would greatly benefit from finding a local carb-guy and having it dialed into your setup.
larger cc boosters may help off the line, but I think your best bet is to find an expert...
better to spend the money on experience than buy a new carb that may have similar tunning issues.

my $.02
good luck!
^^ this


for example, i started with a holley HP series 750, he took it and modified it with a HP Ultra series billet baseplate from a 850, among jetting it for my combo etc..

spending more money once > spending hours and hours fvcking with something
 

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Discussion Starter · #16 ·

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Discussion Starter · #18 ·

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Thanks! I am going to start on my wiring project tomorrow. I will be rewiring the Whole Car. I removed the dash and dash hull the other day. Plus,I removed the A/C heating system. I am still looking for a NON A/C Heater Box,if you know anyone that is looking to sell one. Thanks!
 

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Discussion Starter · #20 ·
Thanks! I am going to start on my wiring project tomorrow. I will be rewiring the Whole Car. I removed the dash and dash hull the other day. Plus,I removed the A/C heating system. I am still looking for a NON A/C Heater Box,if you know anyone that is looking to sell one. Thanks!
I knows the feeling...Take your time with the wiring,,,It will save you in the long run.
 
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