intake manifold oil leak, please help

I have a 1990 Firebird, it has the 305 V8 TPI in it. The motor is out of another car that only had 1700 miles on it. The motor is brand new. While installing the intake manifold, we used Permatex sealer on the front and rear of the intake. Unfortunatley, the rear of the intake has a small leak in it. I previuosly owned a 1992 Camaro RS and it had the same problem. I know how to fix the problem mechanically, but does anyone have any other opinions on sealer to use on the intake?

My suggestion is always this, application is the key. Don't mix sealer with a gasket...use one or the other. If you want to use the silicon sealer, use only it and apply it in a uniform 1/8" bead.