I have holes in the top of the flanges of my N33 manifolds right before the carburetors. 4 on the flange near the front of the motor and 2 on the rear. The front 4 are all sealed with bolts; only one of the rear 2 is sealed, the other is sucking air. I don't know a whole lot about vacuum but this doesn't seem right. Also, I'm assuming the flying saucer thing on my distributor is vaccuum advance (?) which is also sealed. What should really be happening with all these sealed holes?

If I remember correctly the N33 is from a early 260. Most of the bolt holes were to hold brackets for water and fuel lines. I can't remember which was what. A picture could help if you have one. The flying saucer IS your vacume advance and should not be blocked. There should be a small vacume hose going from your intake manifold to the nipple on the vacume advance. There should also not be any leaks on your intake manifold. Hope this helps.

I have a recently redone n36 intake and all i left open is the brake booster line in the top left and the bottom egr valve that goes to the crank case , but sucking noise is not good , all the rest of mine are capped

ScoHo was talking about the manifold. Seerex I think your talking about the balance tube.

ahh ok my bad

Scoho , the vacume advance hose should be connected to a vacume port right behind the front carb dome and the manifold. It looks like a little tube about 1/8" in dia. and about 1/2" high. If you connect to manifold vacume it will go to full advance at start up and when you open the throttle and the vacume drops the advance will go to retard. The vacume must be from the carberater.

I'm hoping we're talking about the same port. It's about 2 inches from the left hand 'corner' of the front carburetor on the flange just past the spacer. I also plugged the extra vacuum leak, reinstalled NGKs (What was I thinking!?!?), and rebalanced carbs. Today and tomorrow are going to be rare dry days here, so I get to take it out at least a couple more times. Thanks for the help guys, it really makes a difference.