Silicone Thermostat Water Neck Housing Gasket attempt

Well my experience with the "real gaskets" wasn't a good one. I used their fiberglass reinforced one on my 170 valve cover. Straightened the valve cover till it was dead perfect, tightened to their specs. Leaked like a ****. Tightened "a little more" leaked a little less like a ****. Took it out and replaced it with cork. Leak gone. Screw those rubber over priced pieces of ****.