650 carb on a 383

[MEK-Dangerfield]

Would these be the jets?
I stripped my Holley and got it running v nicely after a thorough clean up, but have no clue of its size. How would one know.
It is fixed on a 400 engine and really performing very well.
Is there a Holley chart with all the relevant numbers on it.
Is the CFM constant with the jet sizes, or one can have a certain CFM and still play around with the jets?
Mine have a 582 stamped on them. What does that mean?
Cheers

You can use the number stamped on your choke tower to reference the carb size. Is that 80128 I see? Judging by the size 58 jets, my guess is this is a 600-650FM carb. 


    Mike

[Challenger_7]

Thanks for the input Mike. Yes it is 80128. Is there a cross reference table somewhere?
C P Also thank you for the info. Actually whilst stripping the carb, part of the power valve chipped, proving your point.
It may seem I am an expert for stripping the carb, but I am not. I took many photos to make sure I put everything back in its place
As such, please tell me what does the power valve do
Farouk

[MEK-Dangerfield]

Thanks for the input Mike. Yes it is 80128. Is there a cross reference table somewhere?
C P Also thank you for the info. Actually whilst stripping the carb, part of the power valve chipped, proving your point.
It may seem I am an expert for stripping the carb, but I am not. I took many photos to make sure I put everything back in its place
As such, please tell me what does the power valve do
Farouk

Farouk,

  From Holley's website, that is a 650 CFM carb that was put on 383's. The real Holley power valve looks a little different than what you have. Most come with a rating of 6.5 from the factory. OK... Here we go... That means when you stomp on the gas and the vacuum drops below 6.5, the power valve opens to let more gas into the mix. I hope I got that right.    In answer to another question you had, the jet sizes vary. You have to look at your spark plugs to know if you need to go up or down in size. If your car is running fine as you said, then you have to be close.. if not "on" with the jets. I notice if I'm 5 or more sizes "off", the car will miss some at cruising speed.


  Mike

[Chryco Psycho]

you are correct Mike , the power stay closed until the vacuum drops below the rating & vacuum inches then opens to enrich the mixture for more power

[Challenger_7]

Thank you guys. This feels so good when suddenly light shines in on dark areas
This carb was verry erratic and thats why I cleaned it up. But one thing very important you guys have tought me now relating to the power valve. I have always suffered from sudden acceleration. If I kick down very quickly, the car will chocke for a few seconds and then wake up. With the accelerator pump working well, I never knew why, but now I do. Hopefully changing the valve will sort it out. Now to try and find a correct one.
Please still bear with me and sorry for "stealing the thread", but not intended:
When you say to change jets (if need be) the bigger the number the more fuel?
When ordering power valves, I need to give the carb number? In this case 80128, right?
Also from what you said that the 650 is for a 383, then for my 400 with a cam (not sure what, but it revs to 6000) then it can do with a slightly bigger one!
CP, Mike, pls have a look at my other thread (http://www.cuda-challenger.com/cc/index.php?topic=45180.new#new). I would appreciate your comments please.
Thanks, Farouk

[dwbiggs]

I run a 750 VS on my 440 combo...see sig.  No jet changes, just a lighter spring.  Runs great...been told I should go to 850 but it runs so good I am afraid to change it.  Don't know how much seat of the pants change I would feel anyway on the street if I changed.

[Challenger_7]

dwbiggs This is an awsome combo you have on there, and I am not sure that even an 850 is adequate for you. Believe me if you ever try a bigger carb, you will definitely feel the difference.
On my 400 challenger which has a cam but I do not klnow what, and it revs upto 6000 rpm, that is how I bought it. Luckily the carb was giving me much headache and I changed it with a newer one that I found here in the market. From information gathered later on, the old carb was around 550 and the current one is 650. Before the change, I had some tire burning on take off only with my foot fully depressed. Now, even whilst cruising at say about 25 mph, if I slap my foot down, my main worry will be to keep the car heading forward from so much spinning tires, and spins tires even on second gear!!!
Stay safe buddy