I'm not sure who made it, but I have a heavy chrome water neck that seals with an O-ring instead of a gasket. When I first assembled the motor it didn't have a thermostat in it, but when I went to put one in a while ago I noticed the neck doesn't have a receiver groove in it for the T-stat..I put it together anyway and it leaked like crazy, so then I cut the edge of the T-stat and sealed it with some crappy clear silicone (all I had at the time). It doesn't leak now, but i'm worried the silicone will blow out and make a real mess...I think what i'll do is sandwich the T-stat between 2 gaskets instead maybe?