thermostat housing issues..
 

I just installed a new intake on my boat, a performace plus high rise intake..basicly a copy of a dart..anyway, I am having an issue with the thermostat housing sealing, I have the set up with the plastic piece in the housing. I have tryed everything, from double gasket, to using silicone, and I cant get it to seal. It almost like its no sitting flush on the intake, anyone have this issue or figure out a fix to this..I know I know, buy a cross over tube..but besides that..