Source for vacuum?

I am adding power brakes during my build. I am using a corvette MC and CJ booster. Whats the best place to tap in for the vacuum needed for the booster? Can I "T" off the PCV hose at the back of the intake?

I am running fenderwell headers so there are no ports there.
Thoughts?

 

The brake booster should have its own connection. There may be an extra one on the carb, if not there should be a plug in the manifold you can remove and install a barb fitting.

 

Yeah, I am sure there will be an extra port in the intake I can tap off of. It's an edelbrok intake, so we'll see tomorrow when I look at it again.
They are like 1/2 NPT barb fittings, right????

 

The booster usually connects to a manifold vacuum port from a fitting on top of the manifold. The booster hose is usually 3/8-1/2" ID, and the fitting has a port that large. Just because it's always hooked up like that, I expect the little 5/32" taps off the carb base will be too small to provide adequate vacuum. Also you have to have manifold vacuum - ported vacuum from the carb won't work.

 

I had an old set of waggy exhaust manifolds that had ports tapped into them.(headers don;t)...but I assumed I'd need intake vacuum.

 

Those were probably for smog connections

 

Yes, air injection, not vacuum.

 

You are correct.


There is no vacuum in the Exhaust manifold. You need intake manifold vacuum.

There should be a port for that on the intake manifold. If not, you could remove the manifold, and drill and tap a place for the vacuum fiting, then re-install the manifold.

Which engine are you running?