I cut a small groove in the center of the wall on the block and on the manifold with a dremel and a cut off wheel. That and use a good amount of rtv and let it set up for 30 min before setting the intake on. I've had my intake off 3 times and never had a problem with leaks.

 

In the process of pulling my intake manifold off (again) due to oil leaking out the back....(runs down the block and right onto my new headers) I am going to try overlapping the RTV sealent this time with the gasket.

 

Are you saying to use a Sealant or Anti-seize. How about a product called
Blue Moly ?? would the anti seize be capable as a sealant also. Appreciate the
great info. I have a 97 Z28 with a bad leak fwd and aft side of Intake Manifold.

 

Sealant not anti-seize. GM recommends Grey RTV and you can use this grade or higher temp rating. The best procedure I've found is to place the intake manifold gaskets in place, put a 3/8" wide bead on both the front and rear block walls..extending up the gaskets about and inch. Put the intake on immediately..waiting before installing the manifold just allows the silicone to skin over and negatively effects the sealing capability....and torque it down. Then wait 24 hours before starting the engine. This works every time I've done it..on several cars. You don't need to do anything other than make sure everything is clean and you'll be succesfull.