Broken ported vacuum switch?

[invader_star]

Hello friends. I am experiencing an odd vacuum leak in my newly rebuilt '89 L The troubled area appears to be from the manifold vacuum line going to the distributor, and then to the white ported vacuum switch on the bottom of the intake manifold. When the engine is running, there is a slight hiss you can hear coming from what seems like the underside of the intake, and the engine idle fluctuates a little bit.. if I plug the manifold vacuum line going to the distributor, the hiss goes away, and the idle smooths out. I feel pretty positive that my ported vacuum switch is broken, because I cleaned the two of them out with compressed air and brake cleaner.. what do you guys think?

I was thinking of bypassing the switches with a piece of vacuum line. Should the vehicle operate normally if I do this? I'm not sure.. vacuum troubleshooting is the worst..

[invader_star]

So, a little update. I bypassed the vacuum port and I'm still having some issues. With the vacuum advance plugged, I set the distributor timing to TDC at operating temp idle. When I attach the vacuum advance, it jumps 12.5 degrees at idle. It runs kinda lame, since the timing is advanced so far, but it appears that you can't control how much advance the vacuum gives?

What is the normal vacuum advance at idle? 12.5 degrees seems much too far.

I measured the pressure from the manifold vacuum, and I get a pretty steady 19psi. I have a spare distributor, and I thought about swapping over the vacuum advance diaphragm... I don't know