This should be a simple question:

I understand that dual plane intakes / manifolds (like my own Performer RPM) has a wall in the inlet that separates one primary + one secondary barrel from the other two prim/sec of the carb (left / right side). Correct me if I`am wrong.

But how long is these flows separated ?? Is it really like each pair of prim/sec feeds 4 cylinder each, through separate channels all the way ??

Or is the air/gas-flow separated just a bit inside the dual-intake?

I havent seen / study my intake manifold from below, so I dont know.

If it is separated all the way, then the idle mixture for each primary will be different for each 4-cylinder pair. Correct?

 

They are completely separated, unless you are using a thick open carb mount gasket.

 

Thanks

OK. So they also then feed each 4 cylinders ?

When I`m going to fineadjust the 2 separate idlemixture screws on carb (Performer 1405), then each of them affect 4 different cylinders ?

If so, what number-serie of cylinder do they feed? On right / left side of the block?

 

It doesn't split up the banks. It splits the firing order. If you look at any two adjacent cylinders, they would be on opposite planes from each other.

 

OK. I assumed that the firing order, not the banks, decided the split.

To get this complete: So if one of the idlemixture screws is delivering too fat mix, it can foul only 4 of the plugs?

 

Well, I wouldn't go that far, because there is a little communication between the banks under the carb base.

They should be adjusted evenly, regardless.

 

OK, the communication you mention is BELOW the manifold, its in the block ?

I have read the idle-mixture adjustment-prosedyre from Edelbrock, but is this the best way, or is it a better way ? I felt that the response / change was little, even if I turned mix-screws a lot.

And when there is two of them it seems to little presice way to do it. But maybe that is normal (?)

I haven`t a vacuum-meter to use, by the way.

(Maybe have to take a search, yeah )

 

Above the manifold, there are vacuum passages between the bores in the base of the carb.