Barracuda Challenger Forum

Author Topic: carb choice  (Read 773 times)

Offline nsmall

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carb choice
« on: January 07, 2017 - 02:30:12 am »
Hello everyone.  so I have a carter carb (rebuilt last year) and changed the nozzles from 28 to 43 as the new Edelbrock Airgap intake and new 355 SG added a major hesitation when I floor it.  There is still a hesitation (although less noticeable)

Sometimes the car really takes off when I floor it, other times it is less scary.  Timing is solid.

Gas lines new, fuel filter new. Carter carb rebuilt by a guy who specializes in carbs.

My friend thinks I am a fool for not switching over to a Holley 750 double pumper.  Is he right?

The engine does seem a little thirsty.

My Cuda's rebuilt 340 has a mild cam, heads machined to 2.02.  Probably adding headers this year.

I love to go fast, I guess I dont care about mpg (unsure if a double pumper means I get horrible mpg's)

Not trying to start some epic carb debate, just curious if you guys think the Holley carb is that much better vs my carter.  I think my carter is a 625.

Thanks guys.

Neil




Offline cudabob496

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Re: carb choice
« Reply #1 on: January 07, 2017 - 03:04:23 am »
340, mild cam, 750 DP way too much carb (I uses a 750 DP for a 500 hp built 440)


what size carb do you have now?
« Last Edit: January 07, 2017 - 03:06:06 am by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
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1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline HP_Cuda

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Re: carb choice
« Reply #2 on: January 07, 2017 - 04:58:50 am »

Heck ya Holley is better than a Carter.

You can even go the variant route and choose a Proform or Quickfuel.

You have options - you can choose a 700cfm vacuum carb and still get good performance and save on fuel when not mashing the skinny pedal on the right. Or you can dump $$$ into a double pumper and lay waste to your fuel budget.

Whatever you want to do.
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Offline GoodysGotaCuda

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Re: carb choice
« Reply #3 on: January 07, 2017 - 06:38:53 am »
I had a decently modified 650 Thunder AVS on my built-up 318 that ran very, very well.

What transmission/converter do you have with that large pump shot? Just putting bigger nozzles in can certainly not help a hesitation problem in some instances. I had large nozzles with mine, but I also had a 3500 stall converter.
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Offline nsmall

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Re: carb choice
« Reply #4 on: January 07, 2017 - 10:57:44 am »
My transmission is a 727.

Stock built, no large stall.

There is a 33 nozzle choice that came in the kit.

Thank folks

Offline YO7_A66

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Re: carb choice
« Reply #5 on: January 07, 2017 - 11:25:47 am »
 How about trying an Air/Fuel sensor kit before swapping carbs? The kit would help you figure out "where" the fuel problem may be and you might be able to keep your existing carb. Your current setup does not call for a real high performance carb unless you have future upgrade plans.

 If you decide to go with a new carb, get a vacuum secondary unit with replaceable bleeds (IFR's, IAB's, PVCR's). Quick Fuel makes many different series of carbs for us street guys. Stay in the 600-700cfm range would be plenty.

 Note: A DP carb does not determine fuel mileage. Tuning a DP carb and your right foot does! I run a QF SS-750-Annular DP on my 340 Challenger. I can cruise 14-14.4 all day long but I run two A/F sensor kits to make sure it is tuned correctly. But my engine and trans are no longer stock.
 
« Last Edit: January 07, 2017 - 12:28:27 pm by YO7_A66 »

Offline Chryco Psycho

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Re: carb choice
« Reply #6 on: January 08, 2017 - 10:11:54 am »
I would be using a Proform race series , probably a 650 cfm , best bang for the $$ , far more responsive & tunable than any AFB style carb

Challenger - You`ll wish You Hadn`t

Offline nsmall

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Re: carb choice
« Reply #7 on: January 08, 2017 - 11:30:41 am »
Chryco Psycho, I'm seeing multiple 650 proforms online.
Could you recommend a specific one?

I'm looking for something decent on mpg and something that doesn't need much tunning once it's set up.  Basically something reliable and I thought that's what Carter's are known for, but my rebuilt Carter needs to go. 

I'm considering having the guy who rebuilt my Carter have another crack at adjusting it now I changed the gears and intake.

Thanks,

Neil

Offline 734406pk

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Re: carb choice
« Reply #8 on: January 08, 2017 - 01:07:32 pm »
Consider installing an AFR gauge, it will be major help in tuning the engine. In the mean time, remove a few spark plugs and check the color of the center electrode insulators. The hesitation issue sounds like it could be on the secondary side of the AFB, which may need to be jetted up or down. Did the previous intake manifold use the exhaust crossover BTW?
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
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Offline YO7_A66

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Re: carb choice
« Reply #9 on: January 08, 2017 - 01:55:22 pm »
 QF and Proform carbs are the same group of people. The QF guys that I have dealt with over the years are damn good carb guys!! You are in good hands with either carb brand.

 https://www.proformparts.com/product-exec/product_id/873/nm/PROFORM_reg_STREET_SERIES_CARBURETOR_b_650_CFM_b_VACUUM_SECONDARY/category_id/182

 https://www.summitracing.com/parts/pro-67207

 https://www.quickfueltechnology.com/carburetors/street/hr-series/
« Last Edit: January 08, 2017 - 02:51:16 pm by YO7_A66 »

Offline nsmall

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Re: carb choice
« Reply #10 on: January 08, 2017 - 07:46:47 pm »
734406pk

The previous intake was a weiand 8007.  Not sure of the cross over, I just wanted a new aluminum intake that was not painted and heard the Edelbrock rpm air gap was a good intake.

Offline 734406pk

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Re: carb choice
« Reply #11 on: January 08, 2017 - 08:10:58 pm »
734406pk

The previous intake was a weiand 8007.  Not sure of the cross over, I just wanted a new aluminum intake that was not painted and heard the Edelbrock rpm air gap was a good intake.

Ah! The Weiand 8007 had an exhaust cross over that heats the intake plenum (unless the cross over ports were blocked by the intake gasket) and the Eddy Airgap doesn't have an exhaust cross over. Street driving in a low ambient temp (< 50 deg F) can have a major effect on fuel atomization since the new Eddy intake can get "cold" at times, causing fuel to form large droplets, which don't want to burn efficiently. This could explain why the hesitation is sometimes worse than other times. What temp thermostat are you running in your 340?
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline Chryco Psycho

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Re: carb choice
« Reply #12 on: January 08, 2017 - 09:15:25 pm »
#67301 :2thumbs:

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Offline nsmall

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Re: carb choice
« Reply #13 on: January 08, 2017 - 09:30:24 pm »
180 is the thermostat

Offline EMCD

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Re: carb choice
« Reply #14 on: January 08, 2017 - 09:56:27 pm »
Why not go EFI? For a few hundred more. You'll never tune it again. Plus, more powder and efficiency.