High-Tack and Aviation Sealer are similar, with Aviation Sealer being slightly thinner in viscocity, but stayin tackier longer. I like High-Tack on stuff like rocker covers and lifter covers, Aviation Sealer works nice on thin gaskets, like trans gaskets and thermostat housings. Seems that #2 si suggested more for threads in the manuals, Ifind that Fel-Pros Plia-Seal works about the same in that application. I do prefer Permatx High Temp Thread Sealent for plugs that go into coolant, though. As far as pricing, Aviation Sealer and High Tack are about the same, maybe a few cents one way or the other.
