Author Topic: Carb help!!  (Read 238 times)

Offline TFlynn72

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Carb help!!
« on: March 19, 2018 - 10:09:20 am »
I have a Cuda with 440, Medium cam, bored .30 over, factory heads but valves have been enlarged, headers. My question is I have a 850 Holley dual pumper and it seems like it may be to much for the motor? What do you think is a good fitment for this engine if it was yours. It does run rich. Thanks!!!!




Offline 70chall440

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Re: Carb help!!
« Reply #1 on: March 19, 2018 - 02:24:58 pm »
I am sure you will get a variety of opinions here but IMO an 850 is too much carb for a mild motor. a lot has to do with how you use the car; are you racing it or just driving it? You could probably rejet the carb to get it to run leaner, adjust the timing, etc. I would probably run nothing more than a 750 or maybe even a 650. You really need a wide band O2 sensor/reader to really dial it in. Plenty of guys here have and are running carbs on 440's to provide much more accurate advice. In my case I normally ran 6 packs on my 440's and relatively recently went to EFI on everything.
Current Mopar
70 Challenger RT 440-6, 73 Cuda (under const)
05 Durango, 99 Dakota, 01 Ram 4x4, 14 2500 4X4, 10 PCP Challenger RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR, 61 Jeep FC170
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline jimynick

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Re: Carb help!!
« Reply #2 on: March 19, 2018 - 09:46:31 pm »
They ran 850's from the factory in Thermoquads, so it may not be the carbs fault alone. Having the ability to determine the actual fuel/air ratios in a live environment is necessary to make the tuning task easier for mere mortals. The power valve and it's rating and functionality are also a key aspect and it's tough to just guess your way to success. If you can find a shop with a chassis dyno and a sniffer you'll be a lot closer to your goal, Good luck  :cheers:

Offline TFlynn72

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Re: Carb help!!
« Reply #3 on: March 20, 2018 - 08:08:35 am »
Thanks for the input!!I will see if I can get it to a shop that can dial the carb in and if not I may move to a 750. Who love to switch to EFI but do not know that much about it?

Offline 70chall440

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Re: Carb help!!
« Reply #4 on: March 20, 2018 - 12:33:08 pm »
Thanks for the input!!I will see if I can get it to a shop that can dial the carb in and if not I may move to a 750. Who love to switch to EFI but do not know that much about it?

With the current systems such as the Fitech mean street and Holley sniper there isnt much t know. Basically install the throttle body (same as bolting on a carb), hook up the 4 or 5 wires, install a )2 sensor, and install a EFI fuel system (this is the harder part) and you are good to go. The fuel system is the hardest part as noted as it requires an EFI pump and return line. The best solution is to get a Tanks Inc. new tank and EFI pump and then connect it. The EFI system learns by itself, no laptop needed. It isnt really that hard at all and the benefits are well worth the effort.
Current Mopar
70 Challenger RT 440-6, 73 Cuda (under const)
05 Durango, 99 Dakota, 01 Ram 4x4, 14 2500 4X4, 10 PCP Challenger RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR, 61 Jeep FC170
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)