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  #1  
Old 01-21-2001, 10:14 PM
70Challenger R/T S.E. 383 70Challenger R/T S.E. 383 is offline
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I need some help on which carb i should use. I dont know much about the engine since i did not build it, but it has headers, edelbrock torker, bigger cam than stock. I used to have a holley 750 on it and it ran great and never bogged. Many people told me that was way too much for a 383, so i gave it to a friend and put a carter 625 on mine. Thats when problems started(some of you know from some of my other posts). I finally got it half way working and drivable put it takes a nice dose of starting fluid to start it and forever to warm up then it still bogs nicely and sometimes backfires through the carb. So, should i ditch the carter and get another holley 750? Maybe a 650 or 700??
Please help. Thanks

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  #2  
Old 01-21-2001, 11:41 PM
Chargerchuck Chargerchuck is offline
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What is your rear axle ratio & trans configuration? I would go with a 750 Holley, vacuum secondaries unless you have an unusually high rear axle ratio. This is even a better choice if you either have a stick or a high stall (2500 RPM plus) converter
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  #3  
Old 01-22-2001, 01:18 AM
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rumblefish360 rumblefish360 is offline
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CC;

If it ran better with the 750 to start, them a return to that carb would be in order. A 625 would be fine for stock or near stock 383's of non-hi performance level.
As soon as the Torker and bigger than stock cam came into the picture. The 750 carb was almost a mandatory thing. Mostly because most people use these 2 things together with the idea of a big increacse over stock power.
It's to late to say "If it ain't broke don't fix it." But now you know what they mean. I give you credit for trying somthing new and trying to improve it though. We've all been down that road!
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  #4  
Old 01-22-2001, 01:45 AM
Dr. Mopar Dr. Mopar is offline
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70 Challanger; I would use a 650 double pumper,or if it is a auto. try a 750 vacume secondary they work well on the street.
Quote:
Originally posted by 70Challenger R/T S.E. 383:
I need some help on which carb i should use. I dont know much about the engine since i did not build it, but it has headers, edelbrock torker, bigger cam than stock. I used to have a holley 750 on it and it ran great and never bogged. Many people told me that was way too much for a 383, so i gave it to a friend and put a carter 625 on mine. Thats when problems started(some of you know from some of my other posts). I finally got it half way working and drivable put it takes a nice dose of starting fluid to start it and forever to warm up then it still bogs nicely and sometimes backfires through the carb. So, should i ditch the carter and get another holley 750? Maybe a 650 or 700??
Please help. Thanks

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  #5  
Old 01-22-2001, 05:27 AM
cdignition cdignition is offline
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If youre looking to find out if your carb is too small for your engine...just run a vacuum gauge on it, and if at WOT it shows any vacuum, its too small....Make sure you run the engine all the way to the maximum operating RPM of your cam/intake combo....It wont matter if youre running Manual or Vac. secondarys for this test, except if the Vac secondarys arent opening properly, it will show alot of Vacuum...
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  #6  
Old 01-22-2001, 05:35 AM
bubby440 bubby440 is offline
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go with the 3310 holley very easy to tune and dependable
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  #7  
Old 01-22-2001, 12:20 PM
Joe Mad 73 Joe Mad 73 is offline
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A carter 625 should work fine on a mild perf. 383. Sounds like to me that you got a POS carb. If it's new take it back and swap it out. I have a Edbl. 600 on my 383,RV type cam,headers and after market intake and it runs nice. But if you had good luck with a 750 holley, go back to one. It's not too big for you.
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  #8  
Old 01-22-2001, 07:59 PM
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70Barracuda 70Barracuda is offline
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I would consider an Edelbrock 750 I have one on my 340 and it runs great. Plus, it's way easier to work on, adjust and it don't have gaskets/power valves to go bad. They dont perform like a Holley. For a street car I like it much more. They are inexpensive also.
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  #9  
Old 01-23-2001, 03:46 AM
Rug_Trucker Rug_Trucker is offline
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I would hate to see you throw that Carter away. I used to run a 625 w/holley street dominatorSingle plane) and stock 383 Magnum in my 70 Bee. It got better mileage than my factory Holley. What type of RPM do youdo? There is a formula for figuring carb size. If you know how fast the motor spins then use the displacement of your engine then you can figure the most effecient carb for your application. Of course thinking ahead to the future mods that you will be doing. Carters are too easy to work on compared to Holley's. Obviously you aren't getting enough gas. Back fire is usually cause it is lean. Is the carb new? Is the choke working properly? Starting fluid can f&*% up a engine in a hurry if you aren't careful. If it is new you might of just missed something when you were doing the swap. It might be something you got in the line when you switched carbs. When you stomp on it does it blow black smoke?

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  #10  
Old 01-23-2001, 04:06 AM
Streetwize Streetwize is offline
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You guys aren't going to believe this, but....

If you take the Factory 68-69 440 AVS carb and use the jet size,metering rods and Air valve screw settings listed in the old Mopar Engine manual for a 440 CH-4B manifold w/o heat you will not believe how strong a mild 383 or 440 will run!!!

I did it just for a joke once and, holy S#$t!! the thing was incredible on a bone stock 69 factory 440 non HP short block with bowl ported 452s, a .484"MP and a Weiand intake and stock log exhausts and Sears whisper quiet mufflers in a '73 duster w/3.23 OPEN gears. It ran 8.40's @ 84 MPH in the 1/8th all day long. That's about 13.2 @ about 104 in the 1/4. It ran 2-3 tenths better than a 3310. It was a real sleeper, I just had 1 tailpipe sticking out (just like a 318), the other was tucked behind the wheelwell. It would regularly bust 5.0's and only cost about $2200 to build.

Wize 1
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  #11  
Old 01-23-2001, 06:13 AM
70Challenger R/T S.E. 383 70Challenger R/T S.E. 383 is offline
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The car is an automatic. I've tried 3 carter 625s, one was totally rebuilt correctly, one was 30 years old with no rebuild, and the one currently on it is from my uncles 70 383 challenger which he gave to me because he got a new edelbrock 650. The one he gave me takes forever to start and some starting fluid but once warmed up , it will start everytime first try no problem. All three of them bogged like hell if you mashed it from under 2000rpm no matter what was done to them. I tried rich jets and rods, lean jets and rods and everything in between. I'm fairly new to carters and am not liking them to far(i wonder why!?), i started out and learned holleys first. Oh and dont worry, i wont throw it the carters away,I'll give them all back to my uncle since he likes the afb/avs design so much.
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  #12  
Old 01-23-2001, 06:21 AM
70Challenger R/T S.E. 383 70Challenger R/T S.E. 383 is offline
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Oh yeah, i would like to get a carb that will work with my future modifications too. I am planning on getting ported and polished stage 6 heads with a MP284/484 or 292/509 cam and 1.6 roller rockers and new 2 inch hooker supercomp headers. How much difference you think i will have once i have the above parts(e.t. and HP gain wise)?
(Try not to let this turn into a big cam/head which is better conflict)
Thanks for all the help.
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  #13  
Old 01-24-2001, 06:09 AM
Rug_Trucker Rug_Trucker is offline
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You need to have a vacuum gauge on your beast to see what is happening when you stomp it. Somebody could have messed with the counter weights. This controls the rate of opening. If you are going to go bigger on the cam check into a Thermoquad. They are 800cfm from the start. Are you familiar with Demon Sizzler? He builds all out Monster TQ's or street/strip carbs. Up to 1000cfm. I think that his 800's can be modified to 930? Not sure. Any way get a vac gauge they are priceless in diagnostics. Super comp headers? On the street? Are you gonna race? That big of headers could actually hurt you. It is probably time to get some engine books and plan on getting everything to work together.

[This message has been edited by Rug_Trucker (edited January 24, 2001).]
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  #14  
Old 01-25-2001, 05:33 AM
70Challenger R/T S.E. 383 70Challenger R/T S.E. 383 is offline
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I know the 2 inch supercomps will hurt with the 383 , but i'm planning on upgrading to a 496 stroker. Probably this summer or so. Im just getting new headers now cause im going to pull the engine and detail the engine bay and stuff and the headers on the car now wont seal and are about to have rust holes in them. I have plenty of engine books too. Im still planning my engine and have plenty of time to get it perfect. ill be pulling the engine,etc. in March, so not to worry.
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  #15  
Old 01-26-2001, 05:39 AM
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amoparguy amoparguy is offline
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From your description of what's happening, I suspect that you have a vacuum leak. If the condition dosen't improve when you swap carbs, I'd look elsewhere. Before you spend a bunch of $$$ swapping carbs, you better determine if you have a vacuum leak. You will never get a decent tune if it does. A vacuum gauge is an invaluable tuning tool. I agree with rug trucker, get a vacuum gauge to see what's happening.If the 383 is stock a 600 vac secondary Holley works well. If you feel you need something larger, go with the 3310 Holley, it's hard to overcarb with vacuum secondaries.

This carb sizing program on the web makes it easy ( no math involved...lol)
http://www.prestage.com/carmath/calc_carbsize.asp

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  #16  
Old 01-26-2001, 07:10 AM
toolman toolman is offline
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I have had a 650, a 750, a 800, and a 850 on my 383. I like the 800 for mine. On yours, the 625 is too small, I would go with at least the 750 Holley or Demon. More info on the motor and drivetrain would help.
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