Edelbrock Carb Question- Vacuum port

Aaron65 said

Neither port is "wrong." GM used manifold vacuum for a lot of their cars back in the '60s, and in some cars, it smooths out the idle and helps to keep the engine cool in traffic. It makes other cars nervous (the idle hunts). Out of my six old cars, three are running ported vacuum and three are running manifold vacuum. Neither has caused any catastrophes.

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That's correct. The important thing is to adjust initial timing accordingly regarding which port you use. So that means it will take a good bit less initial timing if you use the ported vacuum port.

I have used manifold vacuum on the distributor can in the past and I simply left it hooked up and adjusted initial. Worked for me.

That said, even still, I always had the best results using ported vacuum.