440 Six Pack Carburetors - Front vs Back

[MoparHonda]

Are the front and back carburetors in a 440 six pack the same? Can they be swapped/interchanged from front to back?

 

[OH71RRunner]

Yes they are the same. You can tune the front then swap to the back to do the other one.

 

[MoparHonda]

Thank you OH71RRunner, I had kinda suspected they were the same.

 

[72RoadrunnerGTX]

Careful, if you are referring to OE list numbers, most OE configurations in the original production years, had different metering plates in the front and rear carbs, staggered jetting bank to bank and front to rear. Currently available Holley reissues use the same list number for front and rear.

 

[lewtot184]

they aren't the same. the metering plates are jetted differently.

 

[MoparHonda]

Well, if they're not the same, how do I adjust the back carburetor? Will swapping it to the front, adjusting, then putting it back work?

 

[biomedtechguy]

how do I adjust the back carburetor?

Save yourself time, trouble, and less than optimal tuning and get the Promax rear carb throttle plate w/angled idle mixture screws.

 

[MoparHonda]

Thank you, BioMedTechGuy. Makes me wonder why the factory or Holley didn't do this from the start.

 

[72RoadrunnerGTX]

They weren’t meant to be adjusted in the field originally. They were flow adjusted when assembled originally then had a lead plug placed over them to prevent further adjustment.
You will find no reference to adjusting or even anything about the existence of these outboard idle mixture screws in any of factory service manuals of the time.

 

[biomedtechguy]

You will find no reference to adjusting or even anything about the existence of these outboard idle mixture screws in any of factory service manuals of the time

All true, but a whole new world of performance when they are accessible and adjusted, especially on a modded 440.

 

[62MAX]

All true, but a whole new world of performance when they are accessible and adjusted, especially on a modded 440.

If you can find an old Direct Connection manual,the procedure for adjusting the end carbs is there.

 

[MoparHonda]

Thank you, does anyone here have that manual and can you please post a photo of the relevant page(s)?

 

[biomedtechguy]

Thank you, does anyone here have that manual and can you please post a photo of the relevant page(s)?

I can offer you this typed paragraph that was an epiphany and a positive turning point for tuning/setting the idle mixture screws on the outboard carbs:

I have my 70 Service Manual, but I would like to source any
Direct--->Connection info available

 

[MoparHonda]

Thank you very much;

1) Where are the air idle bleed holes?

2) For example, if I cover the air idle bleed hole on the front carburetor and it's rich, do I adjust the front carburetor only? Should I then repeat this procedure on the back carburetor?

 

[62MAX]

Thank you very much;

1) Where are the air idle bleed holes?

2) For example, if I cover the air idle bleed hole on the front carburetor and it's rich, do I adjust the front carburetor only? Should I then repeat this procedure on the back carburetor?

There are four air bleeds inside the air horn,two large and two small.cover the two outer most (large) at the same time then adjust each screw until you get no change in idle speed,do each carb separately front to back then reset idle speed on center carb,you may have to do more than once.

 

[MoparHonda]

Thank you, 62Max, will do as soon as I get an intake manifold problem fixed.

 

[MAPS]

I can offer you this typed paragraph that was an epiphany and a positive turning point for tuning/setting the idle mixture screws on the outboard carbs:
View attachment 620816
I have my 70 Service Manual, but I would like to source any
Direct--->Connection info available

Can sincerely say, Thank you, very much, for this!
This will save me a lot of arguments, as now I have proof this is what DC also stated.
Thank You.
MAPS

 

[MoparHonda]

Thank you, MAP, I'll do this as soon as I get an intake manifold problem fixed.

 

[biomedtechguy]

cover the two outer most (large) at the same time

When I asked about "which ones to cover" I think I was told do the outside bleed on the side you are adjusting, or that it didn't matter which side, or DO BOTH like you said....
So since I can't get to it to try myself for a while, @62MAX , how sure are you that both outer bleeds should be covered at the same time?
Thanks!

 

[62MAX]

When I asked about "which ones to cover" I think I was told do the outside bleed on the side you are adjusting, or that it didn't matter which side, or DO BOTH like you said....
So since I can't get to it to try myself for a while, @62MAX , how sure are you that both outer bleeds should be covered at the same time?
Thanks!

Sure enough !!