[Doug Christie]

Originally Posted by Jimbro727

Awesome! The new intake doesn't have any provisions for an EGR, so it'll be gone all together soon..

I'll plug the thing in the first pic, but what is it and what was it's purpose (just out of curiosity.. the new manifold doesn't have one I noticed)

The PCV valve: I heard that a clogged valve can cause a rough idle, and a slew of other problems.. how can I check this (I guess with the manifold on or off, since I'm changing it anyway).. also.. according to the manual that came with the Holley, there's a place to hook up a PCV valve.. should that be hooked up there? Or is its current location on the manifold alright?

So is the vac line to the modulator in a good place now? Or should it be hooked up to the full manifold vac line on the carb? Or what?

Thank you so much for the response! I figured someone knowledgeable would come along and just clear it all up!

--Jimmy

There were many heat activated vacuum switches to control various pollution control devices back in the day. The heat from the manifold or water crossover would activate the switch and allow a vacuum signal to activate another switch at a pre-determined temp.

You can check your PCV valve by pulling it out of the valley pan and shaking it to see if it rattles. Best to just buy a new one if in doubt. As far as hooking it up with the new manifold, it just heeds a large full vacuum port, like the one that my be on the back of your carb.

The line for your modulator should be hooked up tp a full vacuum source like from the back of your carb that feeds the vacuum to your brake booster.
If you have a vacuum guage, you can check the ports on your carb to see if they are ported or full vacuum. The ports that are near the base of the carb are usually full vacuum.