I've got a Weiand Team G Intake for my 496,but there is no vacuum port for my power brake booster.Any suggestions to fix this?

if you're running a holley you can use the large tube located in the rear of the carb. Or you could also drill and tap a hole just below the carb and install a nipple there.

So I would drill and tap into the intake just below the carb?
If I don't drill and tap a new port what will I do with the pcv valve?

You didn't say what carb you're running, but if it's a holley, just use a T fitting off the rear port of the carb, and run both brakes, and PCV.
That's what I did on my Nova with a victor jr. intake.

The carb is a Holley and the T fitting sounds like an easy fix.
I read where this may not be good for the brake booster,something about oil getting into the booster from the pcv valve.

a lot of the cars from the 70's and 80's had somekind of a filter inline to the booster that I think kept the oil out.