Surge Tank Sealing: Sealant with or w/o gasket?

[RedBarchetta]

I'm in the process of swapping my surge tank for a fabbed aluminum number that I bought from Finishline a while ago. The bracket bolts flush to the intake manifold on one side, while the other side of this bracket mates to an O-ringed waterneck that then extends to the bottom of the tank with a 3" length of 1.5" hose.

Should I mix a typical gasket with a smear of sealant (Black Permatex Ultra) or should I just go sealant alone? I always figured that the gasket sort of helped hold it all together, but the last time I R&Rd the stainless tank (to fix a minor leak) it eventually started to seap, again.

And will that small O-ring be enough to hold back water, or should I also give the outer edge a thin smear of sealant as insurance?

The LAST thing I want to do is bolt this all together and have another pesky drip.

Thanks for the advice.

-Dean

Pic for reference (though the water neck they installed on mine is 1.5" OD and that concerns me a little. However, the connection onto the radiator is the SPF factory 1.625" OD 'tube', so not sure if I need to be too concerned about flow):