'71 Power Brake Booster Check Valve (and thermal sensor)

My '71 has 2 nipples. The big one goes to the intake manifold vacuum source, and the small one has a rubber plug over it. I have a V8 and no A/C.

Edit: I would hazzard a guess to say that your PCV valve should be plumbed into the carb base not the booster. With that gob of silicone, you can't be sure what the OP did. I'll look at my '71 manual today and get back to you.