Vacuum advance

[ColoradoCuda]

I know this has been asked 1 million times, but I have yet to find a satisfactory answer. I have a 71 Cuda with a very stock 383 and an Edelbrock 750 CFM carb. Should I go with the ported or manifold vacuum for my vacuum Advance? Also, any recommendation for initial timing with the vacuum Advance disconnected?

 

[Challenger RTA]

Such a simple question and so many answers. Mine would be. It would depend on how the engine is built and used, if advance is used at all. Requires Deep thought.

 

[Katfish]

I would use ported and at least 6-10 initial.
I had interesting problem when I installed Fitech on my 340.
The gas mileage actually went down and I was stunned.
I found out the port on the Fitech throttle body is too high, and the vacuum advanced never kicked in at light throttle.
I switched to manifold vacuum and it fixed that issue and the gas mileage improved, as expected.
So my advice is, start with ported, and check it.

 

[Xcudame]

Assuming by Stock 383 you also mean a stock points type distributor, than yes, the ported vacuum port that opens up just after the primary throttle plates open up, is the vacuum port to use. At idle, you typically want no vacuum advance and full vacuum advance at highway speeds.