340 SixPack outboard carb question

Author Topic: 340 SixPack outboard carb question  (Read 4357 times)

Offline Jymy

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340 SixPack outboard carb question
« on: November 11, 2010 - 04:43:42 PM »
Hello there,

I understood that 340 six pack outboard carburetor codes are 4789 (front) and 4790 (rear). What´s the difference between these two carbs? Is there any harm if the set up is having two 4790 coded carbs  :clueless:
...and there goes the Challenger, the last american hero, the soul hero, the demigod, the super driver of the golden west. The last beautiful free soul on this planet!




Offline Moparal

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Re: 340 SixPack outboard carb question
« Reply #1 on: November 11, 2010 - 07:02:03 PM »
I believe it is only the jet plates for front and back.  6pks have to be tuned for each app, so it will work for you when tuned right with 2 90's on there

Offline Chryco Psycho

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Re: 340 SixPack outboard carb question
« Reply #2 on: November 11, 2010 - 07:56:42 PM »
I would tune it with the promax plates

Challenger - You`ll wish You Hadn`t

Offline Jymy

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Re: 340 SixPack outboard carb question
« Reply #3 on: November 12, 2010 - 04:45:11 AM »
yes, there will be promax plates installed, so no issues then. Thanks for the verification  :thumbsup:

just for the curiosity... I´m having correct center carb for my T/A with manual transmission but what´s the difference between the center carbs 4791 (for manual) and 4792 (for automatic)? 
...and there goes the Challenger, the last american hero, the soul hero, the demigod, the super driver of the golden west. The last beautiful free soul on this planet!

Offline Roppa440

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Re: 340 SixPack outboard carb question
« Reply #4 on: November 12, 2010 - 10:31:05 AM »
yes, there will be promax plates installed, so no issues then. Thanks for the verification  :thumbsup:

just for the curiosity... I´m having correct center carb for my T/A with manual transmission but what´s the difference between the center carbs 4791 (for manual) and 4792 (for automatic)?

Probably the linkage and jets differ slightly.

Jetting tips for the 340+6

If a completely stock system try increasing the jet size on the centre carb up to #63 each side (manual trans) or #64 (automatic) but leave the outer carbs alone.

If a stock Aluminum Edelbrock Manifold;

----------------------------------Throttle Side--------- Diaphragm Side
Front Carburetor MMO------------- .086----------------------.073
Center Carburetor Jet-------------- #63---------------------- #63
PVCR--------------------------------- .046--------------------- .046
Rear Carburetor MMO--------------- .086-------------------- .073

Same as above but with heat cross-over blocked;

------------------------------------Throttle Side-------- Diaphragm Side
Front Carburetor MMO-------------- .086--------------------- .073
Center Carburetor Jet-------------- #64---------------------- #64
PVCR--------------------------------- .046---------------------- .046
Rear Carburetor MMO----------------.086--------------------- .073
Dave
1970 Challenger R/T
1997 Jeep Grand Cherokee Limited