Ported or manifold vac for overdrive bypass vac switch?

Liams55belvedere said
I have a vacuum kickdown solenoid installed on a 360la a500 overdrive combo, (got the car set up that way) and I'm wondering which vac port to run it to.

Here's the solenoid
View attachment 1716293745
View attachment 1716293746

The idea behind this (I'm told) is that during normal driving, it would go 1, 2, OD. But with this hooked up properly, when you floor it; it should go 1, 2, 3.

Yup, manifold vacuum.
I set the vacuum switch on my A500 up, but found I really didn’t need it.
If I want out of lockup and/or OD I just turn it off.

The motor pulls good enough where I don’t need to take it out for passing.