Timing and carburetor

[Sammy]

Hi out there, 

yesterday I checked everything with my ignition and timing from greasing distributor 
to new rotor and adjusting dwell. New battery etc.
Runs great now. 

What I'm curious about is idling speed and timing. 
I switched to Edelbrock some years ago.

The shop manual says idle speed is correct when in "D" 480rpm. 
I build in a very small tachometer in the glove box to keep an eye on idling speed 
and managed to set it. 
BUT: When adjust timing it says again 480rpm, but with vacuum advance disconnected. 
Is this in "D" too? Which vacuum port of the Edelbrock carb do you use ?
As for all instructions they say only use the upper one, but the Cadillac runs - in my opinion - 
only smooth when I use the lower one.
I was wondering about that too.

Thanks and have a nice day,

Sammy

[Matti Roth]

Upper port gives ported vacuum. Original carb gives intake vacuum which you get from lower port in Edelbrock. So lower port is similar to original setup.

You can find lots of good carb info in Help section of this forum.

[Sammy]

Yes I read through the help section, but was confused after watching some Edelbrock 
videos on Youtube ...

[Sammy]

Thanks for advice. 

When you look at the carb there are two small vacuum connectors at the front.
The left is a little bit higher than the one on the right, that's what I meant with upper 
and lower. I connected mine to the right one (driver side), als Matti wrote vacuum all the 
time while engine is running. Is yours connected to this port too?

I set the idling speed to 480, vacuum advance connected and in "D". 
It's about 600 when in "P". Is this correct?
Then I disconnect the vacuum hose, now the engine runs lower. 
And now someone has to sit in the car, put it in "D" while I'm checking the timing?
That's what is not so clear to me. 

[Sammy]

I see. Thanks.