There is no gasket between the inlet plenum and supercharger but it has to be sealed with something. My 94 service manual calls for Threadlock 262 (EZFZ-19554-B) or equivalent to seal the mating surfaces. I use the threadlock. I've used it many times without any problems. BTW, I also use it to seal the supercharger outlet (top), and the supercharger mating surfaces.