T-stat gasket tach since the parts store had a really thin gasket as opposed to the beefy ones I've gotten from Mr gasket so I wanted some added assurance in addition to the gasket.
Anyways fired it up and had some coolant loss in the exact same spot of the T-stat housing.
I did notice some corrosion pitting in the cast housing when I cleaned it up and I thought the gasket tach would have filled the gap but no... so I'm going to go ahead and get the beefy billet housing from mancini's with a beefier gasket.