That is actually a nice replica manifold. Permatex should work, but why do you have it cakes up on the hose end and not throughout the mating surface?
Try a different hose that fits tighter, better hose clamp. Find out the exact hose diameter when around the pipe and order the Baller hose clamps that people use around her for their radiators etc.
That will properly solve the problem. I wish they made a nice Freddy like that for a rb20
