Thermostat gasket leaking AGAIN!!!!
I made a large oak sanding block for a full sheet of 80 grit paper. And I have a pane of glass (flat!) that I racer tape another piece of 80 grit, and 320 grit to.
Block sand the manifold, I sand the thermostat housing on the glass,
Use whichever sealer you like, leak should be gone.
I use the glass/80/320 grit on warped holley main bodies too. Easy to see when they are flat again.