Vortec Head Troubles

[rn2fine]

As part of my resto on a 72 Suburban I built up a brand new 350 with mainly GM and Edekbrock parts including Edelbrock E-Tec 170 heads and an Edelbrock Vortec Performer manifold. Performance and mileage is great with this Vortec style system. However, two months into driving I experienced a mystery coolant leak. Was losing approximately 12 to 20 ounces of coolant every time I drove the vehicle. No signs of coolant in oil or anywhere visible in the engine compartment. It turned out that coolant was escaping from intake gasket at the rear coolant passage and running down the back of the block. A quick check of the internet, a conversation with a mechanic at a GM dealer, and a conversation with a private mechanic revealed that coolant leaks on the rear of the 350 Vortec intake gasket are very common. The private mechanic advised that I add some extra silicone sealant between the head and the gasket around the coolant passage. The gaskets are really different than anything I have used in the past. Both the GM and the Fel Pro gaskets are hard plastic with silicone rubber impregnated around the ports and passages. Again, the Vortec setup is awesome, just prone to leaks from what I have heard and now experienced. Anyone dealt with this before?