Demon Street 625 Carb on 440 RC?

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Jun 19, 2016 | 04:48 PM
  #1  
I have an '86 RC with low compression 440/auto/3.55 gears/33's that has dual plane Edelbrock intake, Lunati Voodoo cam with 213/220 duration, .454/.475 lift, 108 CL, headers...

I've always had a hard time getting the carb right, the carb on it now is an Edelbrock Thunder Series 650, not running that great...so was looking at this Street Demon carb that looks like a hi-tech TQ. It's a street driven truck so throttle response and low RPM power is desired.

Would this carb be enough?

Any advice, experience will be accepted. Thanks.
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Jun 26, 2016 | 02:27 PM
  #2  
Have used lots of 600ish cfm carbs in similar applications . Should be fine . Good for low end street driving . Remember to set timing before adjusting carb . Low compression engines usually like lots of advance .
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Jun 27, 2016 | 12:25 PM
  #3  
Quote: Have used lots of 600ish cfm carbs in similar applications . Should be fine . Good for low end street driving . Remember to set timing before adjusting carb . Low compression engines usually like lots of advance .
Thanks for your response "evil one".
I will try that carb out. Will bag the rebuilt carb and go new. And the timing I'll check out...stock is around 12 btdc right? Hopefully I'll get some compression back with heads I'm having rebuilt.
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Jun 27, 2016 | 08:31 PM
  #4  
Set total timing . a combination of base and centrifugal .Should be 34-36 degrees for BB mopar .
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Aug 19, 2019 | 06:50 PM
  #5  
Quote: I have an '86 RC with low compression 440/auto/3.55 gears/33's that has dual plane Edelbrock intake, Lunati Voodoo cam with 213/220 duration, .454/.475 lift, 108 CL, headers...

I've always had a hard time getting the carb right, the carb on it now is an Edelbrock Thunder Series 650, not running that great...so was looking at this Street Demon carb that looks like a hi-tech TQ. It's a street driven truck so throttle response and low RPM power is desired.

Would this carb be enough?

Any advice, experience will be accepted. Thanks.
I put the Street Demon on my 5.9L. It's been running good for months now. However when I am cruising in 3rd gear and punch it, it chokes up and just won't go. Not sure if it's a trans issues or a carb issue. Any thoughts out there?
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Aug 19, 2019 | 07:21 PM
  #6  
Not enough pump shot? Too small of secondary jets? Float level too low? Insufficient fuel flow from the pump?

Does the trans downshift when you punch it?
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Aug 20, 2019 | 03:55 PM
  #7  
Quote: Not enough pump shot? Too small of secondary jets? Float level too low? Insufficient fuel flow from the pump?

Does the trans downshift when you punch it?
Thanks. Well, when the new carb was installed earlier this year, the fuel pump was also replaced. This choking/no down-shifting happened last month as well. When it first happened, I got it warm, gave it a good shot of carb cleaner, drove it, and the trans downshifted properly. But after about two weeks, it's back to choking and not downshifting when I punch it. If it's relevant at all, the idle was just adjusted and return spring was replaced... but the issue was identical before those two changes. Thoughts?
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Aug 20, 2019 | 05:23 PM
  #8  
i think you need to look at your kick down linkage and figure out why it is not working. if it is not dropping into 2nd gear of coarse it is going to choke on all the extra fuel it is getting.
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Aug 20, 2019 | 06:52 PM
  #9  
Quote: i think you need to look at your kick down linkage and figure out why it is not working. if it is not dropping into 2nd gear of coarse it is going to choke on all the extra fuel it is getting.
Thanks. The carb will kick down after start-up in P or N, it's just when I punch it when driving... it will not drop to 2nd gear, etc.
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Aug 20, 2019 | 08:42 PM
  #10  
That's the kickdown linkage for the trans. Need to make sure it is hooked up, and adjusted properly.
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