Vacuum advance from Carb

[Duster_71]

Hello All,

I'm trying to determine if my car is currently set up for the best results. I have a 1974 Duster with a 318 from 1968 with electronic ignition and Edelbrock 1405, no emissions. Currently, the vacuum line for the distributor advance is plugged into the right port (timed/ported) of the carb. I've seen where it might be beneficial to move to the left/lower port (full/manifold) side of the carb for non-emissions. I'm a bit perplexed and didn't want to arbitrarily switch it over and mess things up so I thought I would ask the folks that have dealt with this stuff, mainly you all. Share your thoughts and experiences.

v/r
Ron

 

[Woods74]

http://www.hotrodders.com/forum/distributor-tuning-theory-part-1-a-59033.html


My engine runs best on ported. It's a slug on manifold.

 

[RustyRatRod]

Usually for a street driven car, you have the best results on the ported vacuum source. Sometimes those with very large cams can benefit from the manifold vacuum source.

 

[67cuda360]

if you plan on driving the car on the street (part throttle cruising) keep it on ported (right side), if all you are doing is full-throttle pulls (track) you can play with manifold. Only reason to think about using manifold side for a street driven car is when you have a big cam with huge overlap.